❓ How to do something using detectron2

Describe what you want to do, including:

1. what inputs you will provide, if any:
2. what outputs you are expecting:

❓ What does an API do and how to use it?

Please link to which API or documentation you're asking about from
https://detectron2.readthedocs.io/

For meaning of a config, please see
https://detectron2.readthedocs.io/modules/config.html#config-references

NOTE:

1. Only general answers are provided.
   If you want to ask about "why X did not work" for something you did, please use the
   Unexpected behaviors issue template.

2. About how to implement new models / new dataloader / new training logic, etc., check documentation first.

3. We do not answer machine learning / computer vision questions that are not specific to detectron2, such as how a model works, how to improve your training/make it converge, or what algorithm/methods can be used to achieve X.