How to properly control uart operation in raspberry pi?

Question

Python

Hello. I am using pySerial. How to wait until the end of the wirte command?
Here is the code:

The point is that before the start of the transfer of 5 bytes, the 12th leg is pulled up to 1, then lowered to 0.
This is how it looks in operation: That is

, the processor receives the command to send, and processes it in parallel.
How to make commands run sequentially? Need to work with ctsrts ? Or maybe there are other ways?
Can't find any examples..

Answer 1

to get into ser.write and make processing of inclusion of transfer in it??