python Copies the contents of f$\_$in to f$\_$short and f$\_$long depending

on the lengths of the lines in f$\_$in$.$

Lines with a length $<$ n are copied to f$\_$short.

Lines with a length $>=$ n are copied to f$\_$long.

Lines lengths must not include end$-$of$-$line character$($s$).$

Use: short$\_$lines, long$\_$lines $=$ line$\_$lengths$($f$\_$in$,$ f$\_$short, f$\_$long, n$)$