def has_field_warning(meta, field_id):
    """Warn if dataset has existing field with same id."""
    if meta.has_field(field_id):
        print(
            "WARN: Field '%s' is already present in dataset, not overwriting."
            % field_id
        )
        print("WARN: Use '--replace' flag to overwrite existing field.")
        return 1
    return 0