MultiScene.blend does not document the interface for the blend function

[gerritholl]

Describe the bug

I want to use my own custom blend function with MultiScene.blend. However, the documentation for MultiScene.blend is limited and does not include a definition of the interface with the blending function.

To Reproduce

• Open a browser
• Browse to https://satpy.readthedocs.io/en/stable/api/satpy.multiscene.html#satpy.multiscene.MultiScene.blend
• Observe the missing documentation on the API for the blend function

Expected behavior

I would like documentation on the API for the interface with the blend function, so I can reliably code my own

Actual results

No API is documented.

Screenshots