comefrom: <qiyuangong>404_Sum_of_Left_Leaves_1.py
code: def sumOfLeftLeaves( root):
      stack = [root]
      res = 0
      while len(stack) > 0:
          curr = stack.pop(0)
          if curr is not None:
              if curr.left is not None:
                  if curr.left.left is None and curr.left.right is None:
                      res += curr.left.val
              stack.insert(0, curr.right)
              stack.insert(0, curr.left)
      return res
masked: def sample_funcname ( var_0 ) :
      var_1 = [ var_0 ]
      var_3 = 0
      while len ( var_1 ) > 0 :
          var_6 = var_1.pop ( 0 )
          if var_6 is not None :
              if var_6.left is not None :
                  if var_6.left.left is None and var_6.left.right is None :
                      var_3 += var_6.left.val
              var_1.insert ( 0 , var_6.right )
              var_1.insert ( 0 , var_6.left )
      return var_3
  