'Add a callback notification when the connection has closed. The
callback will be passed the connection, the reply_code (int) and the
reply_text (str), if sent by the remote server.
:param method callback_method: Callback to call on close'

def add_on_close_callback(self, callback_method):

    self.callbacks.add(0, self.ON_CONNECTION_CLOSED, callback_method, False)
