title: How to pass a list as an argument to a function in Python
body: <p>So I want to pass two lists into my function. The aim of my program is to solve a system of three linear equations using the Gauss Jordan Method.</p>
  
  <pre><code>import sys
  from  tkinter import *
  
  def elim(x,list_a,list_b):
      r=-list_b[x]/list_a[x]
      for i in range(x-1,len(list_b)+1):
          list_b[i]=list_b[i]+r*list_a[i]
      return list_b
  
  def mhello():
      ma1=a1.get()
      ma2=a2.get()
      ma3=a3.get()
      ma4=a4.get()
      mb1=b1.get()
      mb2=b2.get()
      mb3=b3.get()
      mb4=b4.get()
      mc1=c1.get()
      mc2=c2.get()
      mc3=c3.get()
      mc4=c4.get()
  lista=(int(ma1),int(ma2),int(ma3),int(ma4))
  listb=(int(mb1),int(mb2),int(mb3),int(mb4))
  listc=(int(mc1),int(mc2),int(mc3),int(mc4))
  
  elim(1,lista,listb)
  print(listb)
  </code></pre>
  
  <p>when I do enter the values, I get the following error:</p>
  
  <pre><code>File "C:/Users/madhuri/Desktop/gauss.py", line 29, in mhello
      elim(1,lista,listb)
    File "C:/Users/madhuri/Desktop/gauss.py", line 6, in elim
      list_b[i]=list_b[i]+r*list_a[i]
  TypeError: 'tuple' object does not support item assignment
  </code></pre>
  
  <p>What am I doing incorrectly?
  How can I pass a list to a fucntion as an argument?
  How can I return a list?</p>