How can I set the `physicsShape` of a sprite within a spritesheet within an editor script?

The spritesheet field of the TextureImporter object has type SpriteMetaData[] and SpriteMetaData provides no means to set the physicsShape.

Worse; any attempt to alter one or more sprites from the TextureImporter's spritesheet causes any existing physicsShape objects to be reset to the default [] for every sprite within the spritesheet (not only the ones edited).

I have about 5,000 sprites I want to automatically generate from a script (I already have their dimensions in a separate yaml), without being able to automate their addition this will take me days and days of repetitive mouse clicking. I'm able to alter the aspects of the TextureImporter that I want besides the spritesheet.