Abstract classes in Pyhton. Decorator implementation for pure virtual functions.

pure_virtual.py

# decorator
def pure_virtual(func):
    def closure(*dt, **mp):
        raise NotImplementedError("Method %s is pure virtual" % func.__name__) 
    return closure
 
class Abstarct(object):
    """ Abstract class Class """
    @pure_virtual
    def virtual_method(self): pass # Empty Virtual method
 
 
# >>> Abstarct().virtual_method()
# Traceback (most recent call last):
#   File "abstr.py", line .., in <module>
#     Abstarct().virtual_method()
#   File "abstr.py", line .., in closure
#     raise NotImplementedError("Method %s is pure virtual" % func.__name__) 
# NotImplementedError: Method virtual_method is pure virtual