如何在超过8位的所有数字的4位后插入逗号

def insert_comma(number):
    number_str = str(number)
    length = len(number_str)
    
    if length <= 8:
        return number_str
    
    reversed_str = number_str[::-1]
    result = ""
    
    for i in range(length):
        result += reversed_str[i]
        if (i + 1) % 3 == 0 and (i + 1) != length:
            result += ","
    
    return result[::-1]

# 示例用法
number = 1234567890
result = insert_comma(number)
print(result)