              httpmethods = getattr(attr, 'bind_to_methods', None)
              if httpmethods:
                  httpmethods = [method.lower() for method in httpmethods]
                  dynamic_routes.append((httpmethods, methodname))
  
          ret = []
          for route in self.routes:
              if route.mapping == {'{httpmethod}': '{methodname}'}:
 
</s>
                if methodname in known_actions:
                    raise ImproperlyConfigured('Cannot use @action or @link decorator on '
                                               'method "%s" as it is an existing route' % methodname)
              httpmethods = getattr(attr, 'bind_to_methods', None)
              if httpmethods:
                if methodname in known_actions:
                    raise ImproperlyConfigured('Cannot use @action or @link decorator on '
                                               'method "%s" as it is an existing route' % methodname)
                  httpmethods = [method.lower() for method in httpmethods]
                  dynamic_routes.append((httpmethods, methodname))
  
          ret = []
          for route in self.routes:
              if route.mapping == {'{httpmethod}': '{methodname}'}:
keep add keep keep keep keep keep keep
 Raise exception when attempting to dynamically route to a method that is already routed to. Fixes #940
rest_framework/routers.py