Practical Structure

From main, 

import subfolder import *

tClass = TestClass()

tClass.tcoreDef1():

 

./subfolder/__init__.py

from .core import TestCore

from .data import TestData



class TestClass(TCore, TData)

    def __init__(self):

        super().__init__()

 

./subfolder/core.py

class TCore:

    def tcoreDef1....

 

./subfolder/data.py

class TData:

    def tdataDef1....