def decode$($message$\_$file$)$:

with open$($message$\_$file, $\text{'}$r$\text{'})$ as file:

lines $=$ file.readlines$()$

dictionary $=\{\}$

for line in lines$[$:$5]$:

key, value $=$ line.split$()$

dictionary$[$int$($key$)]=$ value

message $=\text{'}\text{'}.$join$($dictionary$[$int$($i$)]$ for i in lines$[5$:$8])$

return message