The equality and inequality operators are better implemented in C++,
since we need to need to rely on Cppyy's rich comparison if the object
we are comparing ourselves with is not a Python proxy or if it contains
a null pointer. For example, we need to support the comparison to None.

The rest of comparison operators (i.e. those that define order)
can be implemented in Python, throwing a NotImplemented exception
if we are not comparing two proxies to TObject or derivate.