class AliAnalysisFileDescriptor: public TObject

   AliAnalysysDataContainer - Container of data of arbitrary type deriving
      from TObject used for analysis. A container must be connected to the
      output data slot of a single analysis task (producer) , but also as
      input slot for possibly several other tasks (consumers). The connected
      slots must enforce the same data type as the container (or a derived type).
      A container becomes the owner of the contained data once this was produced.

 Containers should be defined by the analysis module using:

   AliAnalysisModule::AddContainer(const char *name, TClass *type);

 A container should be connected to a producer: