human
Solve the following python programming problem given the following code:
#  Define the class.  Planet is the name of the class.
class Planet:
    # note how i can make an argument optional, just like for functions
    def __init__(self, name, diameter=5000):
        """The initialization of my class.
        This is a special method (function) that gets called every time you
        create a new class.  Every method in a class has "self" as the first
        parameter.  The additional parameters to __init__ are the class's
        input parameters (in this case name and diameter).  You can set a
        default value to each parameter (diameter has a default of 5000).
        """
        self.name = name
        self.diameter = diameter
        
    def __str__(self):
        s = "This is {} with a diameter of {}".format(self.name, self.diameter)
        return s
    
#     def __repr__(self):
#         return self.__str__()
Given the above code, generate some markdown instructions for it.
assistant
#Here is the Python code you requested.

The __init__ function is often used to execute something that takes a bit more time than standard operation, maybe like connecting to a remote database and read out some data.
By generating an instance of that class, the data that was read out then stays alive within that object and can be accessed whenever required later on.
For more applicability, let's leave the Mammals alone for now and talk about how to apply classes to Planets, but keep them in mind for later when we discuss inheritance.