In Functions, I handle a payload, how do I stop DigitalOcean storing their data or access the raw payload?

I have been debugging an error with a Function to handle webhooks.

I verify the expected payload of the webhooks with key/signatures.

DigitalOcean is writing their own information into the payload (e.g. __ow_headers, __ow_path, __ow_method).

Although this information is useful, as they are manipulating the payload any verification that I do will fail.

My preferred option is to just access the raw payload which was sent by the originator. Does anyone know how to do this in Python using DigitalOcean Functions?

My backup is to strip out the information I need, however if DigitalOcean or my originator change the payload then the code will break, for this reason it is not preferred.