title: 'None' in python
body: <p>I have a simple program above that creates a BST from a sorted array. It should parse the tree without showing the leaves which are essentially None. Could someone help explain why the program still spits out 'None'. I'm a python NooB and would appreciate any help.I have tried != 'None' along with is None but get the same results.</p>
  
  <pre><code>class Node:
      def __init__(self,value):
          self.value=value
          self.nodeleft=None
          self.noderight=None
  
  def makeBST(ia,start,end,tree):
      if (end &lt; start):
          return None
      mid = (start + end) / 2
      n = Node(ia[mid])
      n.nodeleft = makeBST(ia, start, mid-1, tree)
      n.noderight = makeBST(ia, mid+1, end, tree)
      tree.append(n)
      return n
  
  def printBST(root):
      print 'RR' ,root.value
      if root.nodeleft == None:
          print 'EOT'
      else:    
          print printBST(root.nodeleft)
  
      if root.noderight == None:
          print 'EOT'
      else:    
          print printBST(root.noderight)
  
  if __name__ == '__main__':
      array = [1, 2, 3, 4, 5, 6]
      dic = []
      root = makeBST(array, 0, len(array)-1, dic)
      printBST(root)
  </code></pre>