pyupgrade.py 文件源码

def visit_Call(self, node):
        if (
                isinstance(node.func, ast.Name) and
                node.func.id == 'set' and
                len(node.args) == 1 and
                not _has_kwargs(node) and
                isinstance(node.args[0], SET_TRANSFORM)
        ):
            arg, = node.args
            key = Offset(node.func.lineno, node.func.col_offset)
            if (
                    isinstance(arg, (ast.List, ast.Tuple)) and
                    len(arg.elts) == 0
            ):
                self.set_empty_literals[key] = arg
            else:
                self.sets[key] = arg

        self.generic_visit(node)