Python 重构的设计模式

我有这三个函数，我发现重复所有相同的代码很难看，这一点都不枯燥。 同时，我不确定如何重构这些函数以保持清晰的表达式。 你能推荐点什么吗

谢谢

def download_loc(instance, filename):
    username = instance.username_or_anonymous()
    slug = instance.slug
    filename_with_timestamp = filename_timestamped(instance, filename)
    return "%s/%s/stl/%s" % (username, slug, filename_with_timestamp)

def preview_loc(instance, filename):
    username = instance.username_or_anonymous()
    slug = instance.slug
    filename_with_timestamp = filename_timestamped(instance, filename)
    return "%s/%s/preview/%s" % (username, slug, filename_with_timestamp)

def screenshot_loc(instance, filename):
    username = instance.username_or_anonymous()
    slug = instance.slug
    filename_with_timestamp = filename_timestamped(instance, filename)
    return "%s/%s/screenshot/%s" % (username, slug, filename_with_timestamp)

---

引入第三个函数，该函数将类型名称作为参数。就我个人而言，我只想调用这个函数，但如果它是从很多地方调用的，那么包装它是有价值的

def loc(instance, filename, typename):
    username = instance.username_or_anonymous()
    slug = instance.slug
    filename_with_timestamp = filename_timestamped(instance, filename)
    return "{}/{}/{}/{}".format(username, slug, typename, filename_with_timestamp)

def download_loc(instance, filename):
    return loc(instance, filename, "stl")

def preview_loc(instance, filename):
    return loc(instance, filename, "preview")

def screenshot_loc(instance, filename):
    return loc(instance, filename, "screenshot")

---

引入第三个函数，该函数将类型名称作为参数。就我个人而言，我只想调用这个函数，但如果它是从很多地方调用的，那么包装它是有价值的

def loc(instance, filename, typename):
    username = instance.username_or_anonymous()
    slug = instance.slug
    filename_with_timestamp = filename_timestamped(instance, filename)
    return "{}/{}/{}/{}".format(username, slug, typename, filename_with_timestamp)

def download_loc(instance, filename):
    return loc(instance, filename, "stl")

def preview_loc(instance, filename):
    return loc(instance, filename, "preview")

def screenshot_loc(instance, filename):
    return loc(instance, filename, "screenshot")

---

将类型（stl、预览和屏幕截图）设为另一个参数，并使用一个函数查看相同之处，查看不同之处，封装每个参数。将类型（stl、预览和屏幕截图）设为另一个参数，并使用一个函数查看相同之处，查看不同之处，封装每个。请注意，

%

运算符不赞成使用

str.format

。请注意，

%

运算符不赞成使用

str.format

。