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<section id="advanced-argument-passing">
<span id="id1"></span><h1>Advanced Argument Passing<a class="headerlink" href="#advanced-argument-passing" title="Link to this heading"></a></h1>
<p>This is a very, very nifty Python feature – it really lets you write dynamic programs.</p>
<section id="keyword-arguments">
<h2>Keyword arguments<a class="headerlink" href="#keyword-arguments" title="Link to this heading"></a></h2>
<p>When defining a function, you can specify only what you need – in any order</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [151]: </span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span><span class="p">(</span><span class="n">x</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">y</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">z</span><span class="o">=</span><span class="mi">0</span><span class="p">):</span>
<span class="go"> print(x,y,z)</span>
<span class="gp"> .....:</span>
<span class="gp">In [152]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">)</span>
<span class="go">1 2 3</span>
<span class="gp">In [153]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">z</span><span class="o">=</span><span class="mi">3</span><span class="p">)</span>
<span class="go">1 0 3</span>
<span class="gp">In [154]: </span><span class="n">fun</span><span class="p">(</span><span class="n">z</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">y</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
<span class="go">0 2 3</span>
</pre></div>
</div>
<section id="a-common-idiom">
<h3>A Common Idiom:<a class="headerlink" href="#a-common-idiom" title="Link to this heading"></a></h3>
</section>
<section id="can-set-defaults-to-variables">
<h3>Can set defaults to variables<a class="headerlink" href="#can-set-defaults-to-variables" title="Link to this heading"></a></h3>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [156]: </span><span class="n">y</span> <span class="o">=</span> <span class="mi">4</span>
<span class="gp">In [157]: </span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span><span class="p">(</span><span class="n">x</span><span class="o">=</span><span class="n">y</span><span class="p">):</span>
<span class="go"> print("x is:", x)</span>
<span class="gp"> .....:</span>
<span class="gp">In [158]: </span><span class="n">fun</span><span class="p">()</span>
<span class="go">x is: 4</span>
</pre></div>
</div>
<p>Defaults are evaluated when the function is defined</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [156]: </span><span class="n">y</span> <span class="o">=</span> <span class="mi">4</span>
<span class="gp">In [157]: </span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span><span class="p">(</span><span class="n">x</span><span class="o">=</span><span class="n">y</span><span class="p">):</span>
<span class="go"> print("x is:", x)</span>
<span class="gp"> .....:</span>
<span class="gp">In [158]: </span><span class="n">fun</span><span class="p">()</span>
<span class="go">x is: 4</span>
<span class="gp">In [159]: </span><span class="n">y</span> <span class="o">=</span> <span class="mi">6</span>
<span class="gp">In [160]: </span><span class="n">fun</span><span class="p">()</span>
<span class="go">x is: 4</span>
</pre></div>
</div>
<p>This is a <strong>very</strong> important point.</p>
</section>
<section id="function-arguments-in-variables">
<h3>Function arguments in variables<a class="headerlink" href="#function-arguments-in-variables" title="Link to this heading"></a></h3>
<p>When a function is called, its arguments are really just:</p>
<ul class="simple">
<li><p>a tuple (positional arguments)</p></li>
<li><p>a dict (keyword arguments)</p></li>
</ul>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">f</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">,</span> <span class="n">w</span><span class="o">=</span><span class="mi">0</span><span class="p">,</span> <span class="n">h</span><span class="o">=</span><span class="mi">0</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"position: </span><span class="si">{}</span><span class="s2">, </span><span class="si">{}</span><span class="s2"> -- shape: </span><span class="si">{}</span><span class="s2">, </span><span class="si">{}</span><span class="s2">"</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">,</span> <span class="n">w</span><span class="p">,</span> <span class="n">h</span><span class="p">))</span>
<span class="n">position</span> <span class="o">=</span> <span class="p">(</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">)</span>
<span class="n">size</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'h'</span><span class="p">:</span> <span class="mi">10</span><span class="p">,</span> <span class="s1">'w'</span><span class="p">:</span> <span class="mi">20</span><span class="p">}</span>
<span class="o">>>></span> <span class="n">f</span><span class="p">(</span><span class="o">*</span><span class="n">position</span><span class="p">,</span> <span class="o">**</span><span class="n">size</span><span class="p">)</span>
<span class="n">position</span><span class="p">:</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">4</span> <span class="o">--</span> <span class="n">shape</span><span class="p">:</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">10</span>
</pre></div>
</div>
</section>
<section id="function-parameters-in-variables">
<h3>Function parameters in variables<a class="headerlink" href="#function-parameters-in-variables" title="Link to this heading"></a></h3>
<p>You can also pull the parameters out in the function as a tuple and a dict:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="go">def f(*args, **kwargs):</span>
<span class="go"> print("the positional arguments are:", args)</span>
<span class="go"> print("the keyword arguments are:", kwargs)</span>
<span class="gp">In [389]: </span><span class="n">f</span><span class="p">(</span><span class="mi">2</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="n">this</span><span class="o">=</span><span class="mi">5</span><span class="p">,</span> <span class="n">that</span><span class="o">=</span><span class="mi">7</span><span class="p">)</span>
<span class="go">the positional arguments are: (2, 3)</span>
<span class="go">the keyword arguments are: {'this': 5, 'that': 7}</span>
</pre></div>
</div>
<p>This can be very powerful…</p>
</section>
<section id="passing-a-dict-to-str-format">
<h3>Passing a dict to str.format()<a class="headerlink" href="#passing-a-dict-to-str-format" title="Link to this heading"></a></h3>
<p>Now that you know that keyword args are really a dict,
you know how this nifty trick works:</p>
<p>The string <code class="docutils literal notranslate"><span class="pre">format()</span></code> method takes keyword arguments:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [24]: </span><span class="s2">"My name is </span><span class="si">{first}</span><span class="s2"> </span><span class="si">{last}</span><span class="s2">"</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">last</span><span class="o">=</span><span class="s2">"Barker"</span><span class="p">,</span> <span class="n">first</span><span class="o">=</span><span class="s2">"Chris"</span><span class="p">)</span>
<span class="gh">Out[24]: </span><span class="go">'My name is Chris Barker'</span>
</pre></div>
</div>
<p>Build a dict of the keys and values:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [25]: </span><span class="n">d</span> <span class="o">=</span> <span class="p">{</span><span class="s2">"last"</span><span class="p">:</span><span class="s2">"Barker"</span><span class="p">,</span> <span class="s2">"first"</span><span class="p">:</span><span class="s2">"Chris"</span><span class="p">}</span>
</pre></div>
</div>
<p>And pass to <code class="docutils literal notranslate"><span class="pre">format()</span></code> with <code class="docutils literal notranslate"><span class="pre">**</span></code></p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [26]: </span><span class="s2">"My name is </span><span class="si">{first}</span><span class="s2"> </span><span class="si">{last}</span><span class="s2">"</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="o">**</span><span class="n">d</span><span class="p">)</span>
<span class="gh">Out[26]: </span><span class="go">'My name is Chris Barker'</span>
</pre></div>
</div>
<p>Kinda handy for the dict lab, eh?</p>
<p>This:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="nb">print</span><span class="p">(</span><span class="s2">"</span><span class="si">{}</span><span class="s2"> is from </span><span class="si">{}</span><span class="s2">, and he likes "</span>
<span class="s2">"</span><span class="si">{}</span><span class="s2"> cake, </span><span class="si">{}</span><span class="s2"> fruit, </span><span class="si">{}</span><span class="s2"> salad, "</span>
<span class="s2">"and </span><span class="si">{}</span><span class="s2"> pasta."</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="n">food_prefs</span><span class="p">[</span><span class="s2">"name"</span><span class="p">],</span>
<span class="n">food_prefs</span><span class="p">[</span><span class="s2">"city"</span><span class="p">],</span>
<span class="n">food_prefs</span><span class="p">[</span><span class="s2">"cake"</span><span class="p">],</span>
<span class="n">food_prefs</span><span class="p">[</span><span class="s2">"fruit"</span><span class="p">],</span>
<span class="n">food_prefs</span><span class="p">[</span><span class="s2">"salad"</span><span class="p">],</span>
<span class="n">food_prefs</span><span class="p">[</span><span class="s2">"pasta"</span><span class="p">]))</span>
</pre></div>
</div>
<p>Becomes:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="nb">print</span><span class="p">(</span><span class="s2">"</span><span class="si">{name}</span><span class="s2"> is from </span><span class="si">{city}</span><span class="s2">, and he likes "</span>
<span class="s2">"</span><span class="si">{cake}</span><span class="s2"> cake, </span><span class="si">{fruit}</span><span class="s2"> fruit, </span><span class="si">{salad}</span><span class="s2"> salad, "</span>
<span class="s2">"and </span><span class="si">{pasta}</span><span class="s2"> pasta."</span><span class="o">.</span><span class="n">format</span><span class="p">(</span><span class="o">**</span><span class="n">food_prefs</span><span class="p">))</span>
</pre></div>
</div>
<p>Note that this is particularity useful when the same value is used in multiple places in the format string.</p>
</section>
</section>
<section id="keyword-only-arguments">
<span id="id2"></span><h2>Keyword Only Arguments<a class="headerlink" href="#keyword-only-arguments" title="Link to this heading"></a></h2>
<p>The usual function signature looks something like:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span> <span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="s1">'this'</span><span class="p">,</span> <span class="n">key2</span><span class="o">=</span><span class="s1">'that'</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="n">key1</span><span class="p">,</span> <span class="n">key2</span><span class="p">)</span>
</pre></div>
</div>
<p>In this case, we have two positional parameters and two keyword parameters.</p>
<p>But all four can be passed as either positional or keyword arguments:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [21]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">)</span>
<span class="go">1 2 3 4</span>
<span class="gp">In [22]: </span><span class="n">fun</span><span class="p">(</span><span class="n">pos1</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">pos2</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">key2</span><span class="o">=</span><span class="mi">4</span><span class="p">)</span>
<span class="go">1 2 3 4</span>
</pre></div>
</div>
<p>or out of order:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [23]: </span><span class="n">fun</span><span class="p">(</span><span class="n">key1</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">pos2</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">pos1</span><span class="o">=</span><span class="mi">3</span><span class="p">,</span> <span class="n">key2</span><span class="o">=</span><span class="mi">4</span><span class="p">)</span>
<span class="go">3 2 1 4</span>
</pre></div>
</div>
<p>And the positional arguments are all required:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [24]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">3</span><span class="p">)</span>
<span class="gt">---------------------------------------------------------------------------</span>
<span class="ne">TypeError</span><span class="g g-Whitespace"> </span>Traceback (most recent call last)
<span class="nn"><ipython-input-24-5ef8442810a5></span> in <span class="ni"><module></span><span class="nt">()</span>
<span class="ne">----> </span><span class="mi">1</span> <span class="n">fun</span><span class="p">(</span><span class="mi">3</span><span class="p">)</span>
<span class="ne">TypeError</span>: fun() missing 1 required positional argument: 'pos2'
</pre></div>
</div>
<p><strong>But:</strong> Notice that you can either have a required argument with no keyword, or an optional argument with a keyword (and a default). And keyword arguments can also be passed as positional arguments.</p>
<p>This was considered less than ideal – with some APIs, you want to require a keyword be used – and you may have a required argument that you want users to pass as a keyword (rather than positional) argument.</p>
<p>In Python 3 – “keyword only” arguments were added:</p>
<p><a class="reference external" href="https://www.python.org/dev/peps/pep-3102/">https://www.python.org/dev/peps/pep-3102/</a></p>
<p>So you can do:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span> <span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="o">*</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="s1">'this'</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="n">key1</span><span class="p">)</span>
</pre></div>
</div>
<p>Now the user can only provide a value for key1 as a keyword argument. If they pass a third positional argument, it’ll be an error:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [26]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">)</span>
<span class="gt">---------------------------------------------------------------------------</span>
<span class="ne">TypeError</span><span class="g g-Whitespace"> </span>Traceback (most recent call last)
<span class="nn"><ipython-input-26-057c5c08ae41></span> in <span class="ni"><module></span><span class="nt">()</span>
<span class="ne">----> </span><span class="mi">1</span> <span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">)</span>
<span class="ne">TypeError</span>: fun() takes 2 positional arguments but 3 were given
</pre></div>
</div>
<p>So Python will not just move that third argument along for you. You need to use the keyword:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [29]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="mi">3</span><span class="p">)</span>
<span class="go">1 2 3</span>
</pre></div>
</div>
<p>But you can still let it be the default:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [30]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">)</span>
<span class="go">1 2 this</span>
</pre></div>
</div>
<p>However, with keyword only arguments you can make it required by providing no default:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span><span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="o">*</span><span class="p">,</span> <span class="n">key1</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="n">key1</span><span class="p">)</span>
</pre></div>
</div>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [32]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">)</span>
<span class="gt">---------------------------------------------------------------------------</span>
<span class="ne">TypeError</span><span class="g g-Whitespace"> </span>Traceback (most recent call last)
<span class="nn"><ipython-input-32-0dfacfcc443e></span> in <span class="ni"><module></span><span class="nt">()</span>
<span class="ne">----> </span><span class="mi">1</span> <span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">)</span>
<span class="ne">TypeError</span>: fun() missing 1 required keyword-only argument: 'key1'
</pre></div>
</div>
<p>So you HAVE to provide it, and you HAVE to provide it as a keyword argument.</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [34]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="s1">'that'</span><span class="p">)</span>
<span class="go">1 2 that</span>
</pre></div>
</div>
<section id="what-about-args">
<h3>What about <code class="docutils literal notranslate"><span class="pre">*args</span></code>?<a class="headerlink" href="#what-about-args" title="Link to this heading"></a></h3>
<p>Asside from allowing keyword-only paramters with or without defaults, a key addition is that you can now have variable numbers of positional arguments, without them getting confused with the keyword arguments:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span> <span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="s1">'this'</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">key1</span><span class="p">)</span>
</pre></div>
</div>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [36]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">)</span>
<span class="go">1 2 () this</span>
<span class="gp">In [37]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">)</span>
<span class="go">1 2 (3,) this</span>
</pre></div>
</div>
<p>Notice how the third argument did NOT get assigned to key1?</p>
<p>And you can pass any number in:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [39]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">,</span><span class="mi">6</span><span class="p">,</span><span class="mi">7</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="s1">'that'</span><span class="p">)</span>
<span class="go">1 2 (3, 4, 5, 6, 7) that</span>
</pre></div>
</div>
<p>This is actually the primary motivation for the PEP – it makes a cleaner separation of positional and keyword arguments.</p>
<p>So for ALL the features in one function:</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="k">def</span><span class="w"> </span><span class="nf">fun</span> <span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="n">key1</span><span class="o">=</span><span class="s1">'this'</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="nb">print</span><span class="p">(</span><span class="n">pos1</span><span class="p">,</span> <span class="n">pos2</span><span class="p">,</span> <span class="n">args</span><span class="p">,</span> <span class="n">key1</span><span class="p">,</span> <span class="n">kwargs</span><span class="p">)</span>
</pre></div>
</div>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [42]: </span><span class="n">fun</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span> <span class="n">this</span><span class="o">=</span><span class="s1">'that'</span><span class="p">,</span> <span class="n">fred</span><span class="o">=</span><span class="s1">'bob'</span><span class="p">)</span>
<span class="go">1 2 (3, 4) this {'this': 'that', 'fred': 'bob'}</span>
</pre></div>
</div>
<p>or:</p>
<div class="highlight-ipython notranslate"><div class="highlight"><pre><span></span><span class="gp">In [44]: </span><span class="n">args</span> <span class="o">=</span> <span class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">)</span>
<span class="gp">In [45]: </span><span class="n">kwargs</span> <span class="o">=</span> <span class="p">{</span><span class="s1">'this'</span><span class="p">:</span><span class="s1">'that'</span><span class="p">,</span> <span class="s1">'fred'</span><span class="p">:</span><span class="s1">'bob'</span><span class="p">}</span>
<span class="gp">In [46]: </span><span class="n">fun</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
<span class="go">1 2 (3, 4) this {'this': 'that', 'fred': 'bob'}</span>
</pre></div>
</div>
<p>Lots of Flexibility!!</p>
</section>
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