Initialize firebase-admin (Python)

pip install firebase-admin

# https://pypi.org/project/firebase-admin/
firebase-admin==3.0.0

# check ifIS_GOOGLE = ... # is current environment Cloud Functions or external serverPROJECT_ID = ...default_app = Nonedef init_firebase():    import firebase_admin    from firebase_admin import credentials    global default_app    if default_app:        return default_app    if not IS_GOOGLE: # no credential needed for Cloud Functions        cred = credentials.ApplicationDefault()    else:        cred = credentials.Certificate('keys/firebase-adminsdk.json')    default_app = firebase_admin.initialize_app(cred, {      'projectId': PROJECT_ID,    })    return default_app