class ReadDatabase(object):

    f_type_list = ReadDatabase.getFTypes() ## 'ReadDatabase' not defined

    @staticmethod
    def getFTypes():
        <reads from database>
        return my_list

from ReadDatabase import *
class MyTreeView (ttk.Treeview):

    def __init__(self,  frame=None, list=[], column_headers=[]):
        for f_type in ReadDatabase.f_type_list:
           <do stuff>