'Retrieves the canonical list of scopes for this access token.
Overrides client.Credentials.retrieve_scopes. Fetches scopes info
from the metadata server.
Args:
http: httplib2.Http, an http object to be used to make the refresh
request.
Returns:
A set of strings containing the canonical list of scopes.'

def retrieve_scopes(self, http):

    self._retrieve_info(http)
    return self.scopes
