大神帮我看看这个问题吧？新手小白刚学习 找不到错误
class Dog():def _init_(self,name,age):
self.name=name
self.age=age
def sit(self):
print(self.name.title()+" is now sitting.")
def roll_over(self):
print(self.name.title()+" rolled over!")
my_dog=Dog('willie',6)
print("My dog's name is "+ my_dog.name.title()+".'")
print("My dog is "+str(my_dog.age)+" years old.")
my_dog=Dog('willie',6)提示这行错误，调用类Dog 不对吗？
