python upload big file example

Hi Gregory,

<<<CHUNK_SIZE = 4 * 1024 * 1024>>>

Is there any reason why you chose 4mb in your python example code? (thanks BTW)

Why chose between a single files_upload call, and a chunked upload session, at 4mb when 150mb is the upper limit for the former? Also why transmit in 4mb blocks when 150mb is permitted? 

Is 4mb preferred for some reason? Is there some efficiency gain? I see that it has been claimed that 4mb is DropBox's chunk size for de-duplication. Is this a factor. or were just intending to minimise resources in your demonstration snippet? 

http://blog.fosketts.net/2011/07/11/dropbox-data-format-deduplication/

Thanks