Will perform func with argument self after inject_instance is called on classkey

    classkey is some identifying string, tuple, or object

def decorate_postinject(func, classkey=None, skipmain=False):
    """
    Will perform func with argument self after inject_instance is called on classkey

    classkey is some identifying string, tuple, or object
    """
    #import utool as ut
    global __CLASSTYPE_POSTINJECT_FUNCS__
    assert classkey is not None, 'must specify classkey'
    #if not (skipmain and ut.get_caller_modname() == '__main__'):
    __CLASSTYPE_POSTINJECT_FUNCS__[classkey].append(func)
    return func