Blockpy: #37.3) hot and cold a scientist has been recording observations of the temperature for the past while. on hot days, they write "h", and for cold days, they write "c". instead of using a list, they kept all of these observations in a single long string (e. g., "hch" would be a hot day, followed by a cold day, and then another hot day). write a function add_hot_cold that consumes a string of observations and returns the number of hot days minus the number of cold days. to accomplish this, you should process each letter in turn and add 1 if it is hot, and -1 if it is cold. for example, the string "hch" would result in 1, while the string "chcc" would result in -2. you cannot use the built-in count method or the len function. unit test your function.