'Sets which NLU webservice to emulate among those supported by Rasa'

def __create_emulator(self):

    mode = self.config[u'emulate']
    if (mode is None):
        from rasa_nlu.emulators import NoEmulator
        return NoEmulator()
    elif (mode.lower() == u'wit'):
        from rasa_nlu.emulators.wit import WitEmulator
        return WitEmulator()
    elif (mode.lower() == u'luis'):
        from rasa_nlu.emulators.luis import LUISEmulator
        return LUISEmulator()
    elif (mode.lower() == u'api'):
        from rasa_nlu.emulators.api import ApiEmulator
        return ApiEmulator()
    else:
        raise ValueError(u'unknown    mode    :    {0}'.format(mode))
