def once(a_project, *arguments):
    l_class_name = None
    if arguments:
        l_class_name = arguments[0]
    class_execute(a_project, "Once features",
                  lambda a_class, a_buffer:
                      a_project.fetch_class_once(a_class, a_buffer),
                  l_class_name)
Register this object as a (multi-channel) listener on the bus.
dataset/ETHPy150Open tioui/Vim_Eiffel_IDE/pyplugin/eiffel_class.py/once--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/cherrypy/cherrypy/process/plugins.py/SimplePlugin.subscribe