如何获取字典中特定关键字最大的字典？

def get_max_dict(dictionary, keyword):
    max_value = None
    max_key = None

    for key, value in dictionary.items():
        if keyword in key:
            if max_value is None or value > max_value:
                max_value = value
                max_key = key

    if max_key is not None:
        max_dict = {max_key: max_value}
        return max_dict
    else:
        return None