def METHOD_NAME(self, error_msg, search_in, feature_name, feature_dict):
    if feature_dict.get("disabled") is not None:
        return
    group = feature_dict.get("group", "")
    if not group:
        return
    if isinstance(group, str):
        group = group.split()
    for f in group:
        impl_dict = search_in.get(f)
        if not impl_dict or "disable" in impl_dict:
            continue
        raise AssertionError(error_msg +
            "in option 'group', '%s' already exists as a feature name" % f
        )