def definition_updated_message(payload):
    """
    Build a Slack notification about an updated definition.

    """
    definition_url = payload['definition']['url']
    definition_name = payload['definition']['name']

    message = 'The <{}|{}> definition was just updated.'
    message = message.format(definition_url, definition_name)

    attachments = [
        {
            'fallback': message,
            'color': 'warning',
            'author_name': 'Mode',
            'author_link': 'https://modeanalytics.com/',
            'title': 'Definition Updated :heavy_exclamation_mark:',
            'text': message
        }
    ]

    return attachments