Handle an operation using the specified function

        @param operation: function to call for this operation
        @param operation_name: operation name. if unspecified operation.__name__ is used
        @param sender_kwarg: optional keyword arg on operation to feed in sender name

def handle(self, operation, operation_name=None, sender_kwarg=None):
        """Handle an operation using the specified function

        @param operation: function to call for this operation
        @param operation_name: operation name. if unspecified operation.__name__ is used
        @param sender_kwarg: optional keyword arg on operation to feed in sender name
        """
        if not self._consumer:
            self._consumer = DashiConsumer(self, self._conn,
                    self._name, self._exchange, sysname=self._sysname)
        self._consumer.add_op(operation_name or operation.__name__, operation,
                              sender_kwarg=sender_kwarg)