def GetCredentials(package_name, scopes, client_id, client_secret, user_agent,
                   credentials_filename=None,
                   api_key=None,  # pylint: disable=unused-argument
                   client=None,  # pylint: disable=unused-argument
                   oauth2client_args=None,
                   **kwds):
    """Attempt to get credentials, using an oauth dance as the last resort."""
    scopes = util.NormalizeScopes(scopes)
    client_info = {
        'client_id': client_id,
        'client_secret': client_secret,
        'scope': ' '.join(sorted(scopes)),
        'user_agent': user_agent or '%s-generated/0.1' % package_name,
    }
    for method in _CREDENTIALS_METHODS:
        credentials = method(client_info, **kwds)
        if credentials is not None:
            return credentials
    credentials_filename = credentials_filename or os.path.expanduser(
        '~/.apitools.token')
    credentials = CredentialsFromFile(credentials_filename, client_info,
                                      oauth2client_args=oauth2client_args)
    if credentials is not None:
        return credentials
    raise exceptions.CredentialsError('Could not create valid credentials')
Attempt to get credentials, using an oauth dance as the last resort.