'Registers a function that is called when the blueprint is
registered on the application.  This function is called with the
state as argument as returned by the :meth:`make_setup_state`
method.'

def record(self, func):

    if (self._got_registered_once and self.warn_on_modifications):
        from warnings import warn
        warn(Warning('The    blueprint    was    already    registered    once    but    is    getting    modified    now.        These    changes    will    not    show    up.'))
    self.deferred_functions.append(func)
