def render_operation_response(response):
    """
    Renders the provided operation response.

    :param response: response to render
    :return: rendered string
    """
    if response['successful']:
        if 'operation' in response and response['operation']:
            return 'Started: {}'.format(response['operation'])
        else:
            return 'OK'
    else:
        return 'Failed: {}'.format(response['failure'])