Currently memoryview does not support subclassing:

>>> class B(memoryview): pass
... 
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: type 'memoryview' is not an acceptable base type


Subclassing memoryview can be useful when
- class A supports the buffer protocol;
- class B wraps class A and should support the buffer protocol provided by class A;
- class A does not support subclassing.

In this situation,

class B(memoryview):
    def __new__(cls, a):
        return super(B, cls).__new__(cls, a)

where a is an instance of class A, would let instances of B support the buffer protocol provided by a.


Is there any particular reason why memoryview does not support subclassing?