(self, index)
return index in self._contents
Check whether ``instance[index]`` has any errors.
Check whether ``instance[index]`` has any errors.
Check whether instance [ index ] has any errors .
def __contains__(self, index):
        """
        Check whether ``instance[index]`` has any errors.
        """

        return index in self._contents
def __contains__ ( self , index ) : return index in self . _contents