The new functions are:
   static Int_t GetGlobalDayFromDate(Int_t date);
   static Int_t GetDateFromGlobalDay(Int_t day);
   static Int_t GetLegalGlobalDayFromDate(Int_t date);
These functions are convenient when a series of dates is required.

See https://root.cern.ch/phpBB3/viewtopic.php?f=21&t=22515

  the problem mentioned [here](https://sft.its.cern.ch/jira/browse/ROOT-8305)

  [here](https://sft.its.cern.ch/jira/browse/ROOT-8385)

spell check,
white spaces,
make proper headers for methods.

provide helper function in `PyMethodBase` to call python code from string with error handling in local namespace

Publish List of method arguments only when it is complete/ready to avoid using it too early in another thread.

Thanks Dan Riley for finding this.