Write a method called letterPositions$()$ which takes in two strings and returns a tuple. The first string can be a phrase of any length while the second one will always be a single character. The tuple that the method returns must contain the index of all occurrences of the second string inside the first string. Be sure to not discriminate between upper and lower case $($i$.$e$.$: a and A should be the same character$).$ If the resulting output is an empty tuple, simply return the empty tuple.

Outside the method, prompt the user for a phrase, a letter, and then print out the resulting tuple as per the sample outputs.