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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 impersonate(self, name=None, lifetime=None, mechs=None, usage='initiate'):
 """Impersonate a name using the current credentials This method acquires credentials by impersonating another name using the current credentials. :requires-ext:`s4u` Args: name (Name):
 the name to impersonate lifetime (int):
 the desired lifetime of the new credentials, or None for indefinite mechs (list):
 the desired :class:`MechType` OIDs for the new credentials usage (str):
 the desired usage for the new credentials -- either 'both', 'initiate', or 'accept'. Note that some mechanisms may only support 'initiate'. Returns: Credentials: the new credentials impersonating the given name """


        if rcred_s4u is None:
            raise NotImplementedError("Your GSSAPI implementation does not "
                                      "have support for S4U")

        res = rcred_s4u.acquire_cred_impersonate_name(self, name,
                                                      lifetime, mechs,
                                                      usage)

        return type(self)(base=res.creds)