If the object c is a literal and the type C a builtin type (such as an int) which cannot be instantiated, then the test
c == int(c)can for example be used (as in the Roman Numeral example).
If the object c is however an instance of a class, and we want to check if c is an instance of class C, we can use the test
isinstance(c, C)This will evaluate to True (1) if c is an instance of class C or any of C's sub-classes.