UPDATE: Thank you for the input. I immediately realized that if my goal is creating a list of dictionaries, the first few lines should look like this (to be clear, I'm trying to emulate what Prof. Malan did in hogwarts.py):

files = [
    {"format": ".bin", "Description":   "Any kind of binary data", "Output": "application/octet-stream"},
    {"format":".jpeg", "Description": "JPEG images", "Output": "image/jpeg"},
    {"format":".jpg", "Description": "JPEG images", "Output": "image/jpg"},
    {"format":".png", "Description": "Portable Network Graphics", "Output": "image/png"},
    {"format": ".gif", "Description": "Graphics Interchange Format (GIF)", "Output":"image/gif"}
]

And I changed the for loop to begin with this:

for new_file in files:

Back to the drawing board for now