問題：
This question's answers are a community effort .
這個問題的答案是社區的努力。
Edit existing answers to improve this post.
編輯現有答案以改進這篇文章。
It is not currently accepting new answers or interactions.
它目前不接受新的答案或互動。
For example, if passed the following:例如，如果通過以下內容：
a = []
How do I check to see if a is empty?如何檢查a是否爲空？