Multiple Inheritance on Python

Question

how are you, people? I am facing this problem: I want to get all methods and attributes of 2 classes like the example below

class Person1:
      def __init__(self) -> None:
          self.john_name = "John"
          self.john_age = 36
  
      def get_name_john(self) -> str:
          return self.john_name
  
      def get_age_john(self) -> int:
          return self.john_age
  
  
class Person2:
      def __init__(self) -> None:
          self.ted_name = "Ted"
          self.ted_age = 32
 
      def get_name_ted(self) -> str:
          return self.ted_name
 
      def get_age_ted(self) -> int:
          return self.ted_age
 

class Student(Person1, Person2):
      def __init__(self) -> None:
          super().__init__()
          print(self.john_age)
          print(self.ted_age)
          print(self.get_name_john())
          print(self.get_name_ted())
          print(self.get_age_john())
          print(self.get_age_ted())
 
 
student = Student()

But when I do this I can't access anything from Person2. Maybe someone can help me with it? Thank you for your attention.

Answer 1

You need to add super().__init__() to Person1 and Person2 as well. This is because of Method Resolution Order (MRO).

When __init__() is called in the Student class, the order at which to resolve __init__() is as follows:

Student -> Person1 -> Person2

Because __init__() is only called once, you would only be able to access Person1 which is one down the hierarchy.

After adding super().__init__() to both Person1 and Person2:

class Person1:
      def __init__(self) -> None:
          self.john_name = "John"
          self.john_age = 36
          super().__init__()
  
      def get_name_john(self) -> str:
          return self.john_name
  
      def get_age_john(self) -> int:
          return self.john_age
  
  
class Person2:
      def __init__(self) -> None:
          self.ted_name = "Ted"
          self.ted_age = 32
          super().__init__()
 
      def get_name_ted(self) -> str:
          return self.ted_name
 
      def get_age_ted(self) -> int:
          return self.ted_age
 

class Student(Person1, Person2):
      def __init__(self) -> None:
          super().__init__()
          print(self.john_age)
          print(self.ted_age)
          print(self.get_name_john())
          print(self.get_name_ted())
          print(self.get_age_john())
          print(self.get_age_ted())

The code now works.