human
Solve the following python programming problem given the following code:
def _wait_for_start(self) : 
    'Wait for instance to be started' 
    def validator() : 
        url = '{server}/'.format (server = self.http_url) 
        resp = self.conn_pool.request ('HEAD', url) 
        return (resp.status == 200) 
self._wait_for (self) 

    
    

    Fix the buggy line: self._wait_for (self)
assistant
#Here is Python code to fix the buggy line: self.

self._wait_for (def validator()