Create a function that takes a string of words (or just one word) and converts each word from camelCase to snake_case.
camel_to_snake("magicCarrots") ➞ "magic_carrots"
camel_to_snake("greatApples for aSmellyRhino") ➞ "great_apples for a_smelly_rhino"
camel_to_snake("thatsGreat") ➞ "thats_great"
You won't get more than two capitals in a row (e.g. "DIYFoods" is not given).