Function named bin$\_$len that $$bins$$ a list of strings into a dictionary where the key is an int length of a given string and the associated values are a set of strings of the key$$s length found in the original list.

Example in a test:

assert bin$\_$len$(["$your$",$ "quick", "code"$])==\{3$: $\{"$your$",$ "code"$\},5$: $\{"$quick$"\}\}$

assert bin$\_$len$(["$the$",$ "the", "code"$])==\{3$: $\{"$the$",$ "code"$\}\}$