def add_iscsi_auth_group(client, tag, secrets=None):
    """Add authentication group for CHAP authentication.

    Args:
        tag: Authentication group tag (unique, integer > 0).
        secrets: Array of secrets objects (optional).

    Returns:
        True or False
    """
    params = {'tag': tag}

    if secrets:
        params['secrets'] = secrets
    return client.call('add_iscsi_auth_group', params)