human
Solve the following python programming problem given the following code:
def add_periodic_callback(self, callback, period_milliseconds, cleanup = None) : 
    ' Adds a callback to be run every period_milliseconds until it is removed.' 
    if (callback in self._periodic_callbacks) : 
        raise ValueError ('Callback added as a periodic callback twice') 
cb = _AsyncPeriodic (callback, period_milliseconds, io_loop = period_milliseconds._loop) 
    def remover() : 
        cb.stop () 
        self._remover (callback, self._periodic_callbacks, cleanup) 
self._periodic_callbacks [callback] = remover 
    cb.start () 
    return remover 

    
    

    Fix the buggy line: cb = _AsyncPeriodic (callback, period_milliseconds, io_loop = period_milliseconds._loop)
assistant
#Here is Python program to fix the buggy line: cb = _AsyncPeriodic (callback, period_milliseconds, io_loop = period_milliseconds.

cb = _AsyncPeriodic (callback, period_milliseconds, io_loop = self._loop)