# If this is an issue with pickle, it is because pickling and 
# unpickling a file needs to take place within a loop with access
# to the class that ctreated the pickle in the first place as explained below:

'''
Classes (and functions) are not pickled,
only references to how to find the same class again in your program are stored. 
Instances then are loaded by creating a new instance of that class and loading unpickled data into the new instance. 
If you removed a class, then you can't load the pickle anymore. 
'''

A technical solution can be found below:
https://stackoverflow.com/questions/40287657/load-pickled-object-in-different-file-attribute-error/40288996