The generic function pattern implemented for methods

singledispatchmethod.py

from functools import singledispatch


class singledispatchmethod(object):
    def __init__(self, method): 
        self.method = singledispatch(method)

    def register(self, klass, method=None):
        return self.method.register(klass, func=method)

    def __get__(self, instance=None, owner=None):
        if instance or owner:
            def _method(*args, **kwargs):
                method = self.method.dispatch(args[0].__class__)
                return method.__get__(instance, owner)(*args, **kwargs)

            _method.__isabstractmethod__ = self.__isabstractmethod__
            _method.register = self.register
            return _method
        else:
            return self

    @property
    def __isabstractmethod__(self):
        return getattr(self.method, '__isabstractmethod__', False)