Why am I getting a different result?

Hi Donald!

Thanks for reaching out. 

Does the issue still persist? 

I see a gap of 4 executions between the last two code cells (ref. the second screenshot) - what cells have you executed prior to running the last cell from the second screenshot? 

It is possible that restarting the kernel and rerunning all code cells in the given order helps you avoid obtaining the difference. Can you please retry?

Hope this helps but please feel free to get back to us should you need further assistance. Thank you.
Kind regards,
Martin