如何在不使用python内置方法的情况下将列表中的单词大写？

def uppercase_words(word_list):
    new_list = []
    for word in word_list:
        new_word = ''
        for char in word:
            ascii_value = ord(char)
            if 97 <= ascii_value <= 122:  # 小写字母的ASCII范围
                new_char = chr(ascii_value - 32)  # 转换为大写字母的ASCII码
            else:
                new_char = char
            new_word += new_char
        new_list.append(new_word)
    return new_list

word_list = ['apple', 'banana', 'orange']
result = uppercase_words(word_list)
print(result)