DateTime :: month - Get number of month
The function returns the month of the year from the date value, i.e. iMonths from the iYears-iMonth-iDays date value.
Return value:  Month ( int32  )
Month of the year according to the Gregorian Calendar.
Implementation overview
-  - internal feature (not documented)
 DateTime :: month (  )
-  - internal feature (not documented)
 DateTime :: month ( iMonth )

