function that run once for all objects

[bowlofred]

Why not set a class attribute in the __init__? New objects can check if it exists and use the data, or if it doesn't exist assume it's the first object and create the data.

import random

class MyClass():
    info = 0

    def __init__(self):
        if self.info == 0:
            #configure things
            print(f"Configuring class info on first use.")
            MyClass.info = random.randint(1000, 100000)
        print(f"Created new object {id(self)}.  Class info is {self.info}")

[MyClass(), MyClass(), MyClass()]

Output:
Configuring class info on first use.
Created new object 4366991120.  Class info is 81133
Created new object 4366990976.  Class info is 81133
Created new object 4367286480.  Class info is 81133