input: def dropLeafNodes(head):
      """ Function to recursively remove leaf nodes from a Huffman tree.
      >>> dropLeafNodes(1) is None
      True
      >>> dropLeafNodes((1, (2, 4, 5), (3, 6, 7)))
      (1, (2, None, None), (3, None, None))
      """
      
      # If node is not None and doesn't have any children 
      if head and not head.left and not head.right: 
          return None
    
      # Don't change anything if head is None 
      if not head: 
          return None
    
      # Recursively call dropLeafNodes on left and right subtrees
      head.left = dropLeafNodes(head.left) 
      head.right = dropLeafNodes(head.right) 
    
      # Return head of the modified tree
      return head
output:     
      if isinstance(head, tuple):
          if len(head) == 3:
              left, right = head[1], head[2]
              left = dropLeafNodes(left)
              right = dropLeafNodes(right)
              if left is None and right is None:
                  return None
              return (head[0], left, right)
          else:
              return None
      return head
  