[ros-users] tf transformation

Hi ,
I want to use tf transforms(_geometry_msgs__TransformStamped) to find the
transformation(trans) between two transformations(say tf1 and tf2).
Basically,
tf1 = trans*tf2
Is this possible to do in python without explicitly publishing the tf1 and
tf2 and subscribing to the trans? Seems like its a trivial function that
should exist.

Eohan