Populate once static variable from static method Python within a class

Question

I have a Class A in Python and I would like to populate the a static variable calling a static method like:

Class A:
   arr = []

   @staticmethod
   def FillArr():
       #do more stuff but for semplicity...
       A.arr = [[2,2,2,]]

  FillArr.__func__()

when I run the code I got 'NameError: name A not defined' so essentially I can't initialize the arr static variable. Essentially once the the class has been instantiated once I would like to populate the static variable

Answer 1

This runs flawlessly on Python 3.6:

class A:
   arr = []

   @staticmethod
   def fillArr():
       #do more stuff but for simplicity...
       A.arr = [[2,2,2,]]

A.fillArr()

print (A.arr)

Or, with the extra info in your comment:

class A:
    arr = []

    @staticmethod
    def fillArr():
        #do more stuff but for simplicity...
        A.arr = [[2,2,2,]]

    def __init__ (self):
        if not A.arr:
           A.fillArr ()

A ()

print (A.arr)