If I run apt show transferpy after being installed, it says:

Depends: cumin, python3:any (>= 3.2~)

However, it does not show python3-yaml dependency. This is not a huge issue, as currently it depends on cumin, which depends on python3, but if that changes in the future, it should be fixed to depend directly on python3-yaml.

I thought dependencies where added automatically, based on python detected dependencies?