Create a function which returns the word in the string, but with all the fog letters removed. However, if the string is clear from fog, return "It's a clear day!".
clear_fog("sky") ➞ "It's a clear day!"
clear_fog("fogfogFFfoooofftogffreogffesGgfOogfog") ➞ "trees"
clear_fog("fogFogFogffoObirdsanffodthebffoeffoesGGGfOgFog") ➞ "birdsandthebees"
f, o or g.