topping2 challenge

Hi,

I am working on below challenge.
http://codingbat.com/prob/p196458

Given a map of food keys and their topping values, modify and return the map as follows: if the key "ice cream" has a value, set that as the value for the key "yogurt" also. If the key "spinach" has a value, change that value to "nuts".

topping2({"ice cream": "cherry"}) → {"yogurt": "cherry", "ice cream": "cherry"}
topping2({"spinach": "dirt", "ice cream": "cherry"}) → {"yogurt": "cherry", "spinach": "nuts", "ice cream": "cherry"}
topping2({"yogurt": "salt"}) → {"yogurt": "salt"}

i have not understood above description. pleASE advise