interesting feedback from person on reddit when I shared this script (I wrote an article on my own site to archive this script and talk about it and share it with others who aren't on here) and it goes like:
There's a problem with either the script or the blockchain.info api where the number of tx field doesn't match the actual number of tx sent.
In other words,
assert( len(addrdata['txs']) < addrdata['n_tx'] )
fails.