How to Make a call stack work

Here is a call stack in python, yayayayayay

Code

class Callstack(Linecounter):
  def __init__():
    this.callstack = []
  def push(code, lnum):
    this.callstack.push([code, lnum])
  def pop():
    super().linenum = this.callstack.pop()
class Linecounter():
  def __init__():
    this.linenum = 0
  def increment(x):
    this.linenum += x
cstack = new Callstack()
linecount = new Linecounter()
cstack.push("main", 0)
linecount.increment(100)
cstack.pop()[0] #linenum now is 0, and there is nothing in the callstack