What is meant by "A new class should do the 'right thing'' python code example

Example 1: python classes

class Box(object): #(object) ending not required
  def __init__(self, color, width, height): # Constructor: These parameters will be used upon class calling(Except self)
    self.color = color # self refers to global variables that can only be used throughout the class
    self.width = width
    self.height = height
    self.area = width * height
  def writeAboutBox(self): # self is almost always required for a function in a class, unless you don't want to use any of the global class variables
    print(f"I'm a box with the area of {self.area}, and a color of: {self.color}!")

greenSquare = Box("green", 10, 10) #Creates new square
greenSquare.writeAboutBox() # Calls writeAboutBox function of greenSquare object

Example 2: python class

class Animal(object): # Doesn't need params but put it there anyways.
    def __init__(self, species, price):
        self.species = species # Sets species name
        self.price = price # Sets price of it
    
    def overview(self): # A function that uses the params of the __init__ function
        print(f"This species is called a {self.species} and the price for it is {self.price}")

class Fish(Animal): # Inherits from Animal
    pass # Don't need to add anything because it's inherited everything from Animal
 
salmon = Fish("Salmon", "$20") # Make a object from class Fish
salmon.overview() # Run a function with it
dog = Animal("Golden retriever", "$400") # Make a object from class Animal
dog.overview() # Run a function with it