method Temporal.CalendarProtocol.yearMonthFromFields
          
CalendarProtocol.yearMonthFromFields(fields: YearOrEraAndEraYear & MonthOrMonthCode,options?: AssignmentOptions,): Temporal.PlainYearMonth 
      
fields: YearOrEraAndEraYear & MonthOrMonthCode
      
    optional
options: AssignmentOptions