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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _decorate_fun(self, fun):
 """Decorate function fun"""


        msg = "Function %s is deprecated" % fun.__name__
        if self.extra:
            msg += "; %s" % self.extra

        def wrapped(*args, **kwargs):
            warnings.warn(msg, category=DeprecationWarning)
            return fun(*args, **kwargs)

        wrapped.__name__ = fun.__name__
        wrapped.__dict__ = fun.__dict__
        wrapped.__doc__ = self._update_doc(fun.__doc__)

        return wrapped