def METHOD_NAME(*types):
    if not is_buck2():
        return ""
    if len(types) <= 1:
        fail("union must have more than 1 type")
    # TODO(nga): `eval_type` won't be needed
    #   when we get rid of string literals as types
    result = native.eval_type(types[0])
    for t in types[1:]:
        result = result | t
    return result