def METHOD_NAME(self):
    """Default method to create BearerToken generator."""
    conf = self.config.get('access_token_generator', True)
    access_token_generator = create_token_generator(conf, 42)
    conf = self.config.get('refresh_token_generator', False)
    refresh_token_generator = create_token_generator(conf, 48)
    conf = self.config.get('token_expires_in')
    expires_generator = create_token_expires_in_generator(conf)
    return BearerTokenGenerator(
        access_token_generator=access_token_generator,
        refresh_token_generator=refresh_token_generator,
        expires_generator=expires_generator,
    )