Can anyone please help me in understanding the following python code

[bhk755 at gmail.com]

Got It!!!,  Finally.  Thanks Dave 

So, the control goes back to the place after the recursive function is called once the no. of element is equal to one and starts merging after which it will again start to split the remaining items. 

Thank you Chris for your multiple explanations.

One final question, Is there a way to edit the message once it has been posted?