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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 auth_with_token(self, token, tenant_id=None, tenant_name=None):
 """ If a valid token is already known, this call will use it to generate the service catalog. """

        # Implementation note:
        # Rackspace auth uses one tenant ID for the object_store services and
        # another for everything else. The one that the user would know is the
        # 'everything else' ID, so we need to extract the object_store tenant
        # ID from the initial response, and call the superclass
        # auth_with_token() method a second time with that tenant ID to get the
        # object_store endpoints. We can then add these to the initial
        # endpoints returned by the primary tenant ID, and then continue with
        # the auth process.
        main_resp, main_body = self._call_token_auth(token, tenant_id,
                tenant_name)
        # Get the swift tenant ID
        roles = main_body["access"]["user"]["roles"]
        ostore = [role for role in roles
                if role["name"] == "object-store:default"]
        if ostore:
            ostore_tenant_id = ostore[0]["tenantId"]
            ostore_resp, ostore_body = self._call_token_auth(token,
                    ostore_tenant_id, None)
            ostore_cat = ostore_body["access"]["serviceCatalog"]
            main_cat = main_body["access"]["serviceCatalog"]
            main_cat.extend(ostore_cat)
        self._parse_response(main_body)
        self.authenticated = True