Do not allow passing None for arbitrary arguments in Function

[ricardoV94]

Description

pytensor/pytensor/compile/function/types.py

Lines 938 to 941 in 3af923b

	# See discussion about None as input
	# https://groups.google.com/group/theano-dev/browse_thread/thread/920a5e904e8a8525/4f1b311a28fc27e5
	if arg is None:
	arg_container.storage[0] = arg

I read the discussion, it's not convincing, and even less now that we have other backends besides the C. If someone wants an Op to accept either None or something else they should define a specific type where None or the something else is allowed. An example of this could be size for RandomVariables or start for MakeSlice.