Installing multi-version ports with portmaster

[Christian Ullrich]

Hello,

how can I use portmaster to install multiple versions of a port, such as 
databases/py-psycopg2?

My default Python version is set to 3.5, but I need psycopg2 for both 
versions. When I have py35-psycopg2 installed and do

     portmaster -m PYTHON_VERSION=python2.7 databases/py-psycopg2

, it replaces the 3.5 version with the 2.7 one, and vice versa. Running 
"make PYTHON_VERSION=python2.7 install" in the port directory works, but 
isn't there a way to make portmaster keep the other port?

Thanks,

-- 
Christian