def get_user(app_configs):
    """
    Looks for either 'api_key_id' or 'email'
    in the provided dict and returns its value.

    Returns None if neither are found or set to
    a valid value

    :param app_configs: a dictionary of all the values in the app.config file
    :type app_configs: dict
    :rtype: [str/None]
    """
    usr = app_configs.get("api_key_id", None)

    if not usr:
        usr = app_configs.get("email", None)

        if not usr:
            return None

    return usr