_product.py 文件源码

def _read_label(key):
    if isinstance(key, ast.Name):
        return key.id
    elif isinstance(key, ast.Num):
        n = key.n
        if isinstance(n, (int, long)) and n >= 0:
            return n
        else:
            raise _errors.TyError("Invalid numeric label.", key)
    elif isinstance(key, ast.Str):
        s = key.s
        if s != "":
            return s
        else:
            raise _errors.TyError("Invalid string label.", key)
    else:
        raise _errors.TyError("Invalid label", key)