human
Solve the following python programming problem given the following code:
def __call__(self, task, values) : 
    "register action that saves the timestamp and check current timestamp

        @raises OSError: if cannot stat C{self._file_name} file
                         (e.g. doesn't exist)
        " 
    def save_now() : 
        return { 
            self._key : self._get_time (), 
} 
task.value_savers.append (save_now) 
    prev_time = values.get (self._key) 
    if (prev_time is None) : 
        return False 
current_time = self._get_time () 
    return self._cmp_op (prev_time, task) 

    
    

    Fix the buggy line: return self._cmp_op (prev_time, task)
assistant
#Here is Python program to fix the buggy line: return self.

return self._cmp_op (prev_time, current_time)