docs: def _get_method(self, rdata):
          """
          Returns jsonrpc request's method value.
  
          InvalidRequestError will be raised if it's missing or is wrong type.
          MethodNotFoundError will be raised if a method with given method name
          does not exist.
          """
          if 'method' in rdata:
              if not isinstance(rdata['method'], basestring):
                  raise InvalidRequestError
          else:
              raise InvalidRequestError
  
          if rdata['method'] not in self.method_data.keys():
              raise MethodNotFoundError
  
          return rdata['method']