tools.py 文件源码

def _get_constant(node, *, types=None):
    if isinstance(node, ast.Constant):
        return node.value
    if isinstance(node, ast.UnaryOp) and isinstance(node.op, ast.USub):
        # FIXME: rely on constant folding for that!
        value = get_constant(node.operand, types=types)
        if value is UNSET:
            return UNSET
        return (-value)
    return UNSET