Returns the number of days in the specified month of the specified year and era.
year An integer from 1 through 9378 that represents the year. month An integer that represents the month, and ranges from 1 through 12 if year is not 9378, or 1 through 10 if year is 9378.era An integer from 0 through 1 that represents the era.
The number of days in the specified month of the specified year and era.