Python去掉内括号，保留外括号

import re

def remove_inner_parentheses(expression):
    # 使用正则表达式匹配内括号及其内容
    pattern = r'\((.*?)\)'
    matches = re.findall(pattern, expression)
    
    # 去除内括号及其内容
    for match in matches:
        expression = expression.replace('('+match+')', '')
    
    return expression

# 测试示例
expression = "(1 + (2 * 3) - (4 / 2))"
result = remove_inner_parentheses(expression)
print(result)