When creating a wrapper class for this API, I encountered issues passing down a flattened dict of kwargs to the constructor of Uniswap() class due to it not having *args, **kwargs in it's constructors signature. Any extra arguments that were not explicitily in the constructors signature would throw an error, which makes it less friendly for other software systems to wrap it's code with.

Simply adding *args and **kwargs to the constructor fixes this issue and doesn't intrtoduce any negative effects.

Simulate can now be specified to return an estimate of the gas fees as well as some other useful metadata for the transaction. Does NOT take into account slippage or price impact for a transaction!!

This was mostly needed so I could find the gas fees ahead of time before pushing an order on-chain and allows me to adjust the amount of network fee token buyback prior to it.

bug fixes when building and pushing transactions

simulate no longer checks balances

*Fixed bug where approved decorator would not check for native token address
*Fixed bug where _is_approved() decorator only checked for positional args and not kwargs