#include <DataFormats/Common/interface/CMS_CLASS_VERSION.h>
Description: Macro used to add versioning info needed by ROOT to a CMS templated class
Usage: Add the following line to a template class' public declaration area CMS_CLASS_VERSION(<number>)
For classes that have been stored into ROOT files before the addition of the macro, we suggest starting the <number> at 10. This was chosen to be larger than any known number of stored changes to a templated class. For new classes that have never been stored, we suggest starting the <number> at 2 (0 and 1 have special meanings to ROOT).