Review content of functor collections
We should ensure that the functor collections (https://gitlab.cern.ch/lhcb/Analysis/-/blob/master/Phys/FunTuple/python/FunTuple/functorcollections.py) do not content redundant information. We should also define which variables are a must and which can be optional; it is certainly the case that some collections already have a distinction, via optional argument.
Example: the Kinematics
collection contains px, py and pt, where the latter is clearly redundant.