def create_zipkin(self) -> Optional[ZipkinConfig]:
    if ('NP_ZIPKIN_URL' not in self._environ):
        return None
    url = URL(self._environ['NP_ZIPKIN_URL'])
    app_name = self._environ.get('NP_ZIPKIN_APP_NAME', ZipkinConfig.app_name)
    sample_rate = float(self._environ.get('NP_ZIPKIN_SAMPLE_RATE', ZipkinConfig.sample_rate))
    return ZipkinConfig(url=url, app_name=app_name, sample_rate=sample_rate)
def create_zipkin(self) -> Optional[ZipkinConfig]:
    if ('NP_ZIPKIN_URL' not in self._environ):
        return None
    url = URL(self._environ['NP_ZIPKIN_URL'])
    app_name = self._environ.get('NP_ZIPKIN_APP_NAME', ZipkinConfig.app_name)
    sample_rate = float(self._environ.get('NP_ZIPKIN_SAMPLE_RATE', ZipkinConfig.sample_rate))
    return ZipkinConfig(url=url, app_name=app_name, sample_rate=sample_rate)