<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def crud_for_app(app_label, urlprefix=None):
 """ Returns list of ``url`` items to CRUD an app. """

    if urlprefix is None:
        urlprefix = app_label + '/'
    app = apps.get_app_config(app_label)
    urls = []
    for model in app.get_models():
        urls += crud_for_model(model, urlprefix)
    return urls