For # UNQ_C3 # GRADED FUNCTION: insert_ones, I wrote the code that passed all tests (yay me), but the plotting function immediately after the unit test throws up an out of bounds error tracing back the insert_ones function. Any suggestions please. Thanks.
Dear Edward Yu,
Many thanks for your prompt response. I had accounted for the case where the active audio clip is close to the end, but I re-examined the code (after a cup of coffee, I might add), and I found a typo in one of the variable names. Correcting the typo made everything right with the world again. 
Saurabh