有关下面Python代码的说法，正确的是
class Num:
def _init_(self, val):
self.Value = val
def_add_(self, other):
return self.Value +
other.Value
def add(self, other):
return self.Value +
other.Value
a = Num(10)
print(a + Num(20),
Num(20)._add_(a)，a.add(Num(20)))
print(a)
