Python script needs some simplification

the following code does just what I want but I feel it is a little bit messy and I want to make it cleaner for better reading in the future, any suggestions?

Enable Python support and load DesignScript library

import clr
from Autodesk.DesignScript.Geometry import *

The inputs to this node will be stored as a list in the IN variables.

dataEnteringNode = IN

Place your code below this line

slider = IN[0]
B = IN[1]
TR = IN[2]
Height = IN[3]
output =
ylst = [0, TR, TR*2]

zlst = range(3)

def create3points():

if 0<=slider < 10:
	zlst[0]= slider
	zlst[1]= 0
	zlst[2]= 0
elif 10<=slider<20:
	zlst[0]= 10
	zlst[1]= (slider-10)
	zlst[2]= 0
elif 20<=slider<=30:
	zlst[0]= 10
	zlst[1]= 10
	zlst[2]= (slider-20)

p1= Point.ByCoordinates(0,ylst[0],Height*zlst[0])
p2= Point.ByCoordinates(0,ylst[1],Height*zlst[1])
p3= Point.ByCoordinates(0,ylst[2],Height*zlst[2])
return output

Assign your output to the OUT variable.

OUT = create3points()