exception documentation

Exception for failed function calls.

Method __gt__ Undocumented
Method __init__ Undocumented
Method __le__ Undocumented
Instance Variable name Undocumented

Inherited from ReturnValueMixin:

Method get_return Undocumented
Method set_return Undocumented
Instance Variable return_node Undocumented
Instance Variable return_variable Undocumented