It seems that a cipher has been used to encode the final code. Mario & Yoshi were the ultimate pairing, once again. Yoshi was able to steal the required key code while being lost in The Great Valley. Mario held on to the algorithm needed to be able to decode the message and has shared it here.
# initialize a variable (text) with the string to be decoded
# initialize a variable (key) with the numeric key
# initialize an empty string (finalCode) to hold the final decoded value
# loop through all characters in text
# determine the integer value of the character using ord()
# shift the integer value back by the key
# determine the char. value of the new integer using chr()
# concatenate the character to finalCode
# print the decoded string (finalCode)
NOTE: You SHOULD actually code this portion