> class Student(object):
  def __init__(self,name):
    self.name = name
  def sayHello(lang):
    print(lang)
    if lang == 'en':
      print('Welcome!')
    else:
      print('你好！')
 
  
> Student.sayHello
<function Student.sayHello at 0x02AC7810>
> a = Student('Bob')
> a.sayHello
<bound method Student.sayHello of <__main__.Student object at 0x02AD03F0
> Student.sayHello('en') # 类调用的时候，将'en'传给了lang参数
en
Welcome!

> a.sayHello() # 类实例对象调用的时候，将对象本身自动传给了lang参数，不能再接收参数
<__main__.Student object at 0x02AD03F0>
你好！
  > a.sayHello('en')  Traceback (most recent call last):  File "<pyshell#7>", line 1, in <module>  a.sayHello('en')  TypeError: sayHello() takes 1 positional argument but 2 were given

# 使用装饰器定义静态方法
> class Student(object):
  def __init__(self,name):
    self.name = name
  @staticmethod
  def sayHello(lang):
    print(lang)
    if lang == 'en':
      print('Welcome!')
    else:
      print('你好！')

      
> Student.sayHello('en') #类调用,'en'传给了lang参数
en
Welcome!

> b = Student('Kim') #类实例对象调用,不再将类实例对象传入静态方法
> b.sayHello()
Traceback (most recent call last):
 File "<pyshell#71>", line 1, in <module>
  b.sayHello()
TypeError: sayHello() missing 1 required positional argument: 'lang'

> b.sayHello('zh') #类实例对象调用,'zh'传给了lang参数
zh
你好！