how to indicate the minimum version of python required?

[Georg Schwarz <georg.schwarz%freenet.de@localhost>]

Yet another probably easy question which leaves me clueless.
The package needs at least python 3.0 (both at build and run times).
I tried

DEPENDS+=       python>=3.0:../../lang/python
...
.include "../../lang/python/application.mk"

which trows

=> Full dependency python>=3.0: NOT found
=> Verifying reinstall for ../../lang/python
bmake[1]: don't know how to make reinstall. Stop


I guess this is because no appropriate buildlink3.mk file is included.
What's the correct way of indicating that dependency?
Do I need to add

PYTHON_VERSIONS_ACCEPTED= 30 31 32 33 34 35 36 37 38 39

but what about python 4.0 coming out?