How to change the color of a specific feature(s) with a PyQGIS script

First of all im a big noob so don't hate. So image that the lines that i have drawn is simple pipeline network, represented by some simple lines in a vector layer. Now the question is, how can i define a script that changes the color of only specific lines to "red"? I tried to write a script from google sources but i failed dramatically. I managed to change the color of the all the lines but i need to specify the "red" color. So far my script is this, but its not working: