(self, key, message)
Replace the keyed message; raise KeyError if it doesn't exist.
Replace the keyed message; raise KeyError if it doesn't exist.
Replace the keyed message ; raise KeyError if it doesn t exist .
def __setitem__(self, key, message):
        """Replace the keyed message; raise KeyError if it doesn't exist."""
        raise NotImplementedError('Method must be implemented by subclass')
def __setitem__ ( self , key , message ) : raise NotImplementedError ( 'Method must be implemented by subclass' )