def _load_secret(self, creds_file):
        '''read the oauth secrets and account ID from a credentials configuration file'''
        try:
            with open(creds_file) as fp:
                creds = json.load(fp)
            return creds
        except Exception as e:
            sys.stderr.write("Error loading oauth secret from local file called '{0}'\n".format(creds_file))
            sys.stderr.write("\tThere should be a local OAuth credentials file \n")
            sys.stderr.write("\twhich has contents like this:\n")
            sys.stderr.write("""
                {
                "account_id": "1234567890001",
                "client_id": "30ff0909-0909-33d3-ae88-c9887777a7b7",
                "client_secret": "mzKKjZZyeW5YgsdfBD37c5730g397agU35-Dsgeox6-73giehbt0996nQ"
                }

              """)
            sys.stderr.write("\n")
            raise e
read the oauth secrets and account ID from a credentials configuration file