Lowercase and Uppercase Map

Write a function that creates a dictionary with each (key, value) pair being the (lower case, upper case) versions of a letter, respectively.

Examples

mapping(["p", "s"]) ➞ { "p": "P", "s": "S" }

mapping(["a", "b", "c"]) ➞ { "a": "A", "b": "B", "c": "C" }

mapping(["a", "v", "y", "z"]) ➞ { "a": "A", "v": "V", "y": "Y", "z": "Z" }

Notes

All of the letters in the input list will always be lowercase.