code: def getVector(self, tree, branchName):
          
  
          if (tree, branchName) in self.__class__.addressDict:
              return self.__class__.addressDict[(tree, branchName)]
  
          itsVector = self._getVector(tree, branchName)
          self.__class__.addressDict[(tree, branchName)] = itsVector
  
          return itsVector
docs: return the ROOT.vector object for the branch.