<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def callback(self, output, inputs=None, state=None, events=None):
        'Form a callback function by wrapping, in the same way as the underlying Dash application would'
        callback_set = {'output':output,
                        'inputs':inputs and inputs or dict(),
                        'state':state and state or dict(),
                        'events':events and events or dict()}
        def wrap_func(func, callback_set=callback_set, callback_sets=self._callback_sets): # pylint: disable=dangerous-default-value, missing-docstring
            callback_sets.append((callback_set, func))
            return func
        return wrap_func