'Returns the handler given the handler\'s name.
This uses the application\'s url mapping.
Args:
handler_name: The __name__ of a handler to return.
Returns:
The handler with the given name.
Raises:
KeyError: If the handler name is not found in the parent application.'

def get_registered_handler_by_name(self, handler_name):

    try:
        return self._handler_map[handler_name]
    except:
        logging.error('Handler    does    not    map    to    any    urls:    %s', handler_name)
        raise
