<!--- Provide a general summary of the issue in the Title above --> 原有可以满足需求， 评论回答在需求页面下。知乎模式更合理，改动较大 ## Expected Behaviour <!--- If you're describing a bug, tell us what should happen --> <!--- If you're suggesting a change/improvement, tell us how it should work --> ## Current Behaviour <!--- If describing a bug, tell us what happens instead of the expected behavior --> <!--- If suggesting a change/improvement, explain the difference from current behavior -->  ## Possible Solution <!--- Not obligatory, but suggest a fix/reason for the bug, --> <!--- or ideas how to implement the addition or change --> ## Steps to Reproduce (for bugs) <!--- Provide a link to a live example, or an unambiguous set of steps to --> <!--- reproduce this bug. Include code to reproduce, if relevant --> 1. 2. 3. 4. ## Context <!--- How has this issue affected you? What are you trying to accomplish? --> <!--- Providing context helps us come up with a solution that is most useful in the real world --> ## Your Environment <!--- Include as many relevant details about the environment you experienced the bug in -->