You have to write functions to perform reading and writing of messages using file operations and write functions for generating a cipher code and ciphering input messages.

All functions for file operations are to be written in $**$fileio$.$py$**$ and functions for ciphering in $**$cipher$.$py$**.$

Messages to be ciphered and the ciphercode is to be read by your program from input files.

The ciphercode is provided in a text file which will have the following structure:

$-$ K: This is just a test

$-$ V: Line two is new to m

$**$K:$**$ indicates the key of the cipher code while $**$V:$**$ indicates the associated value.

In this simple cipher code, each character in the key maps to a corresponding character in value,

where the correspondence is based on sequential ordering.

In the above example, the letter $**$T$**$ is mapped to letter $**$L$**,**$h$**$ to $**$i$**,**$i$**$ to $**$n$**,**$s$**$ to $**$e$**,$ and so on$.$

$1.$ You are to write a file operation function $`$read$\_$keyvalue$($filename$)`$ that reads the file with the ciphercode and

generates two lists of single$-$character strings, one from the key line and another from value line.

$2.$ You are to write ciphering operations to include the function $`$make$\_$dictionary$($l$1,$ l$2)`$ that takes two equal$-$length lists

of single$-$character strings. It creates and returns a dictionary using the elements of l$1$ as keys and the elements of l$2$ as values.

$3.$ Another ciphering operation and corresponding function to write is $`$cipher$($s$,$ d$)`.$ The parameter s is a string and d is the dictionary created by $`$make$\_$dictionary$`.$

Function $`$cipher$($s$,$ d$)`$ uses dictionary d to replace characters in s that are keys in d with the corresponding key value.

Characters in s that are not dictionary keys are left unchanged in the ciphered version of the string s$.$

The function is to return the ciphered string.

$4.$ The string s is to be read from an input file. This should be accomplished by a function $`$read$\_$message$($filename$)`$

as part of file operations, which should open the input file and read all lines in the file treating each

line as the input message to be ciphered. Each line read should be used as s in the function $`$cipher$($s$,$ d$)`.$

$5.$ Each ciphered message returned by the function $`$cipher$($s$,$ d$)`$ should be written to an outfile file.

To do so$,$ you are to write the function $`$write$\_$ciphered$\_$messages$($ciphered$\_$message, filename$)`$ where

ciphered$\_$message is the string returned by $`$cipher$($s$,$ d$)`$ and filename is the name of the file where

ciphered messages are written.

All code for file operations is to be implemented in the file $**$fileio$.$py$**.$

All code for ciphering operations is to be implemented in the file $**$cipher$.$py$**.$

You are already provided with the files and template function definitions. Make sure to add comments to your program.

You are also given code with the main program in file $**$ca$\_00.$py$**.$ This includes all function calls and implements the ciphering system.

$**$Note:$*$

$-$ Please do not change the code structure.

$-$ Usage:

$-$ python ca$\_00.$py $-$kv $-$m

$-$ Example: python ca$\_00.$py $-$kv input$/$ciphercode$.$txt $-$m input$/$messages$.$txt

$-$ Please make sure the code runs when you run the above command from prompt$/$terminal

$-$ All the output files are saved to "output$/"$ folder

A file with ciphercode $($ciphercode$.$txt$)$ and a file with input messages $($messages$.$txt$)$ are

provided for testing: input$\backslash$ciphercode$.$txt and input$\backslash$messages$.$txt$.$

$**$PS$.$ Please do not change: ca$\_00.$py$,$ requirements.txt$.**$

Use $$K:$$ and $$V:$$ to identify key and value of

cipher code $($line$.$startswith$(\text{'}$K$))$

$$ Extract word by $$line$.$split$()$ and extract

character by $$for XXX in YYY$$

$$ Remove K: and V: by using list slicing $[$:$]$

$$ Check list length by using $$len$()$

$$ For dictionary, values of the same key usually

only the last value would be kept

$$ Use $$terminal$$ instead of $$console$$

$$ If $$python$$ does not work, try $$python$3$

$$ Close file after use