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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 controller(self):
 """ Check if multiple controllers are connected. :returns: Return the controller_id of the active controller. :rtype: string """


        if hasattr(self, 'controller_id'):
            if len(self.controller_info['controllers']) > 1:
                raise TypeError(
                    'Only one controller per account is supported.'
                )
            return self.controller_id
        raise AttributeError('No controllers assigned to this account.')