from functools import partial
 
class Tree:
	def __init__(self, op, left, right):
		self.op = op
		self.left = left
		self.right = right
 
	@classmethod
	def reducer(cls, left, right, ops):
		return cls(
			op = ops.pop(0), #shift
			left = left,
			right = right
		)
 
	def __str__(self):
		return '({self.left} {self.op} {self.right})'.format(self=self)
 
 
ops = ['+', '-', '*']
x = [1, 2, 3, 4]
 
reducer = partial(Tree.reducer, ops = ops)
 
ret = reduce(reducer, x)
 
print(ret)

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