stack arithmetic machine kata

# starting with https://www.codewars.com/kata/stack-arithmetic-machine/train/python

import operator


class Machine(object):    
    def __init__(self, cpu):
        self.cpu = cpu
    
    def execute(self, instr):
        iterative_operations = [
            'add', 'sub', 'mul', 'div',
        ]
        instruction, operands = instr.split(' ', 1)
        if instruction == 'push':
            self.push(int(operands))
        elif instruction in iterative_operations:
            self.iterative_stack_operation(instruction, int(operands))
        
    def push(self, value):
        self.cpu.write_stack(value)
        
    def binary_stack_operation(self, operation):
        self.cpu.write_stack(
            operation(
                self.cpu.pop_stack(), 
                self.cpu.pop_stack()
            )
        )
        
    def iterative_stack_operation(self, instruction, count, register_name=None):
        operators_mapping = {
            'add': operator.add,
            'sub': operator.sub,
            'mul': operator.mul,
            'div': operator.floordiv,
        }
        if count < 2:
            return

        for _ in range(count - 1):
            self.binary_stack_operation(
                operators_mapping[instruction]
            )
        
        register_name = register_name or 'a'
        self.cpu.write_reg(register_name, self.cpu.pop_stack())