Provide API Method for Retrieving Revenue Model Phases

Today, while Marketo has the ability to group a Revenue Model's stages into phases, there is no way to access this data outside of the Marketo UI itself. As a Marketo integration developer, I would like to see the phase a Revenue Stage is grouped into via the API in some way, shape, or form.

The most straightforward way to handle this would be to add additional response parameters to Change Revenue Stage activities to include "Old Stage Phase" and "New Stage Phase", but a metadata call to show how the Model is set up would work equally well.