Goal: to make this function without importing any modules -- using Python

Part 1d: Rail Fence Ciphei https://en.wikipedia.org/wiki/Rail fence General Reference & Basic Idea History This is an ancient Greek cipher which implemented with a tool called a scytale s://en wikipedia.org/wiki/Scytale The only change from what's outlined in the article is that we're going to encode all letters in uppercase and all non-letters with the character"." (a period). So, encoding the message "We are discovered, flee at once!" with three rails will be Computer? Will looks like this: "WRIVDLANEAEDSOEE. FE.TOC.. .CR.E. E" The decoding of the above message will be: "WE.ARE.DISCOVERED. .FLEE.AT.ONCE." Note that the Wikipedia article gives the algorithm for both encode and decode (see the solution" section). However, instead of decoding by writing then Imagine writing then ?.EAL.YL.KE.UZZ.ES - - ? Functions rail_encode(num_rails, message): This function accepts num_rails (an int) and a message and returns the encoded message