Filter章节中的一些疑问 about interpy-zh HOT 2 CLOSED

感谢 @oucb 的建议， 这里确实不需要转换成list，去掉后看起来更简明清晰

原著里是这样，我觉得我们可以先于原著改进下，然后再给原著提过去

你来提个PR不？ :) 看看要不要顺便对filter稍微多解释一句

filter(function or None, sequence) -> list, tuple, or string

Return those items of sequence for which function(item) is true. If
function is None, return the items that are true. If sequence is a tuple
or string, return the same type, else return a list.

from interpy-zh.

已提PR。调整了下解释~@suqi

from interpy-zh.