How to write integers to port using PySerial

First of all, writing 123 12 123 123 123 is not a valid Python syntax.

Create a list or a tuple with your integers: values = (1,2,3,4,5)

Now, we need to convert that data into a binary string that represents our values.

So here how we do it

import struct

values = (1,2,3,4,5)

string = b''

for i in values:
    string += struct.pack('!B',i)

# Now send the string to the serial port

Depending on how many bytes you want to use per number, you need to pack them differently. See the documentation here: https://docs.python.org/3/library/struct.html