if node.is_async:
            self.write(" async for ")
        else:
            self.write(" for ")
        self.set_precedence(_Precedence.TUPLE, node.target)
        self.traverse(node.target)
        self.write(" in ")
        self.set_precedence(_Precedence.TEST.next(), node.iter, *node.ifs)
        self.traverse(node.iter)
        for if_clause in node.ifs:
            self.write(" if ")
            self.traverse(if_clause)
    def visit_IfExp(self, node):
        with self.require_parens(_Precedence.TEST, node):
            self.set_precedence(_Precedence.TEST.next(), node.body, node.test)
            self.traverse(node.body)
            self.write(" if ")
            self.traverse(node.test)
            self.write(" else ")
            self.set_precedence(_Precedence.TEST, node.orelse)
            self.traverse(node.orelse)
    def visit_Set(self, node):
        if node.elts:
            with self.delimit("{", "}"):
                self.interleave(lambda: self.write(", "), self.traverse, node.elts)
        else:
            # `{}` would be interpreted as a dictionary literal, and
            # `set` might be shadowed. Thus:
            self.write('{*()}')
    def visit_Dict(self, node):
        def write_key_value_pair(k, v):
            self.traverse(k)
            self.write(": ")
            self.traverse(v)
        def write_item(item):
            k, v = item
            if k is None:
                # for dictionary unpacking operator in dicts {**{'y': 2}}
                # see PEP 448 for details
                self.write("**")