evil.py

import sys
import warnings


class DeprecatedAttribute(object):

    def __init__(self, name, value):
        self.name = name
        self.value = value

    def __get__(self, instance, owner):
        warnings.warn("%s is deprecated" % self.name)
        return self.value

    def __set__(self, instance, value):
        self.value = value


class Module(object):

    client = DeprecatedAttribute('client', 5)


sys.modules[__name__] = Module()