This PR adds type annotations to the api, codec, and crypto files of lab1. These annotations make it much easier to understand the code and determine how to use the functions it provides, at least for me.

I tried my best to determine the types by reading through the code, but there may be a couple errors. I created this to be useful to myself on this lab and as a means of reading through the code, but it would be great to have these type annotations incorporated into future labs.

When trying to add a list to an encoding with add_obj, the current code causes infinite recursion by trying to repeatedly add the list itself. This fixes this error.

Hello,

Unless I'm missing something, I believe this is unintended behavior:

Line 1071 of ag1_runner.py is as follows:

            server._storage.userbase[username] = replace_int(udata, 5, api.OperationCode.PUT_PHOTO, api.OperationCode.REGISTER)

This code does not function as I believe it is intended: instead of replacing the integer value of PUT_PHOTO with the integer value of REGISTER, it replaces the integer value of PUT_PHOTO with the Enum object REGISTER. This results in the decode_log_entry receiving values it items that are neither ints nor bytes types, which would not happen in a real client/server relationship.

To fix this, I think that line 1071 should be replaced with

            server._storage.userbase[username] = replace_int(udata, 5, api.OperationCode.PUT_PHOTO.value, api.OperationCode.REGISTER.value)

This will strictly replace an integer with an integer.