title: Python Matrix Parameter Passing mutated
body: <p>Can someone help me out! 
  I can't find the reason of the error. If I run it 1 time it works fine however when I call the same method again with the same parameters it keep the last session of the list when I never save it. I tried using a temporary variable but even that got modded after I run it once. :(:(
  This algorithm is:</p>
  
  <pre><code>def searchin(position, mattwo):
      listpos = -1
      indexone = -1
      # - - - - - -
      for i in mattwo:
          listpos += 1
          for o in i:
              if o == position:
                  indexone = i.index(o)
                  return listpos, indexone
  
  def repos(reposition, listsone):
      cero, replacement = searchin('0',listsone),searchin(reposition,listsone)
      modded = listsone
      modded[replacement[0]][replacement[1]],modded[cero[0]][cero[1]] = '0', reposition
  
  mat = [['5','4','1'],
         ['0','6','8'],
         ['7','3','2']]
  
  repos('5',mat)
  repos('7',mat)
  </code></pre>
  
  <p>The method serachin() returns the position in the matrix 3x3 of the element we are looking for. Is working fine no errors there</p>
  
  <p>The repos() method is the problem. After I run it, the matrix mat gets mutated with the results of last run BUT I never save that.</p>