问Google cloud speech api在尝试使用时抛出403

EN

from oauth2client.client import GoogleCredentials

GoogleCredentials.from_stream('path/to/your/json')

def make_channel(host, port):
    """Creates an SSL channel with auth credentials from the environment."""
    # In order to make an https call, use an ssl channel with defaults
    ssl_channel = implementations.ssl_channel_credentials(None, None, None)

    # Grab application default credentials from the environment
    creds = GoogleCredentials.from_stream('path/to/your/json').create_scoped([SPEECH_SCOPE])
    # Add a plugin to inject the creds into the header
    auth_header = (
        'Authorization',
        'Bearer ' + creds.get_access_token().access_token)
    auth_plugin = implementations.metadata_call_credentials(
        lambda _, cb: cb([auth_header], None),
        name='google_creds')

    # compose the two together for both ssl and google auth
    composite_channel = implementations.composite_channel_credentials(
        ssl_channel, auth_plugin)

    return implementations.secure_channel(host, port, composite_channel)