WRITE A FUNCTION FOR EACH OF THE FOLLOWING TASKS $(100$ Pts$)$

$($a$)(10$ Pts$)[$Task$-1]$ Define a function called repeat$\_$letters that takes a string and a number $n$ as two parameters and prints the string with every letter repeated $n$ times.

Sample input$/$Output:

print$($repeat$\_$letters$("$medipol$",3))$

"mmmeeedddiiipppooolll"

$($b$)(10$ Pts$)[$Task$-2]$ Define a function called find$\_$index which takes as argument a word and a letter. It will return the index of the second occurrence of the letter in the given word.

Sample input$/$Output:

print$($find$\_$index $("$welcomehome$","$e$"))$

$6$

$($c$)(10$ Pts$)[$Task$-3]$ Define a function called list$\_$unique that takes a string str as an input, checks all letters of the string, and constructs a list that contains the list of character that appear in str$.$ This list should not contain any duplicates.

Sample input$/$Output:

print$(lis{t}_u$nique$(ankara))$

${[}^{\text{'}}a\text{'},\text{'}n\text{'},\text{'}k\text{'},\text{'}r\text{'}]$

$($d$)(10$ Pts$)[$Task$-4]$ Write a function called ngrams$\_$list that takes a string and a number $n$ and return the $n-$grams of the this string as a list

Sample input$/$Output:

print$(ngram{s}_l$ist$(computer,2))$

$[co,om,mp,pu,ut,te,er]$

$2$