I know you are asking for a python library interacting with a node, but let me tell you there is a very comprehensive python library with which you don't need to run a node yourself.
You can find a ...
The problem is that your fee is probably not exactly 165721.
You have 6000000 lovelace
You want to send 5827019 lovelace to recpt_addr
The fee is something like 165721 but not exactly (probably less)