code: def enable(self, policy):
          
          if hasattr(policy, 'href'):
              if not isinstance(policy, InterfacePolicy):
                  raise LoadPolicyFailed('Invalid policy type specified. The policy'
                      'type must be InterfacePolicy')
                  
          self.update(l2_interface_policy_ref=element_resolver(policy))
docs: Set a layer 2 interface policy.
          
          :param str,Element policy: an InterfacePolicy or str href
          :raises LoadPolicyFailed: Invalid policy specified
          :raises ElementNotFound: InterfacePolicy not found
          :return: None