recursion trace to produce different form of recursion tracewe have included an extraneous print statement within our python implementation (line of code fragment the precise format of that output intentionally mirrors output that is produced by classic unix/linux utility named du (for "disk usage"it reports the amount of disk space used by directory and all contents nested withinand can produce verbose reportas given in figure our implementation of the disk usage function produces an identical resultwhen executed on the sample file system portrayed in figure during the execution of the algorithmexactly one recursive call is made for each entry in the portion of the file system that is considered because the print statement is made just before returning from recursive callthe output shown in figure reflects the order in which the recursive calls are completed in particularwe begin and end recursive call for each entry that is nested below another entrycomputing the nested cumulative disk space before we can compute and report the cumulative disk space for the containing entry for examplewe do not know the cumulative total for entry /user/rt/courses/cs until after the recursive calls regarding contained entries gradeshomeworksand programs complete /user/rt/courses/cs /grades /user/rt/courses/cs /homeworks/hw /user/rt/courses/cs /homeworks/hw /user/rt/courses/cs /homeworks/hw /user/rt/courses/cs /homeworks /user/rt/courses/cs /programs/pr /user/rt/courses/cs /programs/pr /user/rt/courses/cs /programs/pr /user/rt/courses/cs /programs /user/rt/courses/cs /user/rt/courses/cs /projects/papers/buylow /user/rt/courses/cs /projects/papers/sellhigh /user/rt/courses/cs /projects/papers /user/rt/courses/cs /projects/demos/market /user/rt/courses/cs /projects/demos /user/rt/courses/cs /projects /user/rt/courses/cs /grades /user/rt/courses/cs /user/rt/coursesfigure report of the disk usage for the file system shown in figure as generated by the unix/linux utility du (with command-line options -ak)or equivalently by our disk usage function from code fragment