(self, callback, insert_pos=None)
Add a user supplied callback. Since callbacks are run serially and share data,
        order can matter.  If the default behavior (to append the callback) is not
        sufficient, insert position can be controlled.

        Arguments:
            callback (Callback): callback object to be registered
            insert_pos (int, optional): position in the list to insert the callback.
                                        Defaults to None, meaning append
Add a user supplied callback. Since callbacks are run serially and share data,
        order can matter.  If the default behavior (to append the callback) is not
        sufficient, insert position can be controlled.
Add a user supplied callback . Since callbacks are run serially and share data order can matter . If the default behavior ( to append the callback ) is not sufficient insert position can be controlled .
def add_callback(self, callback, insert_pos=None):
        """
        Add a user supplied callback. Since callbacks are run serially and share data,
        order can matter.  If the default behavior (to append the callback) is not
        sufficient, insert position can be controlled.

        Arguments:
            callback (Callback): callback object to be registered
            insert_pos (int, optional): position in the list to insert the callback.
                                        Defaults to None, meaning append
        """
        if insert_pos is None:
            self.callbacks.append(callback)
        else:
            self.callbacks.insert(insert_pos, callback)
def add_callback ( self , callback , insert_pos = None ) : if insert_pos is None : self . callbacks . append ( callback ) else : self . callbacks . insert ( insert_pos , callback )