code: def register_method(self, method, fn):
          
  
          # ensure the HTTP verb is not already registered
          if method not in self.methods.keys():
              logger.debug('Service Router ({0} - {1}): Adding method {2} on '
                           'route {3}'
                           .format(id(self),
                                   self.service_name,
                                   method,
                                   self.uri))
              self.methods[method] = fn
  
          else:
              raise RouteAlreadyRegisteredError(
                  'Service Router ({0} - {1}): Method {2} already registered '
                  'on Route {3}'
                  .format(id(self),
                          self.service_name,
                          method,
                          self.uri))
docs: Register an HTTP method and handler function.
  
          :param method: string, HTTP verb
          :param fn: python function handling the request
          :raises: RouteAlreadyRegisteredError if the route is already registered
          :returns: n/a