code: def nth_bizday(n, gyear, gmonth):
      r"""Calculate the nth business day in a month.
  
      Parameters
      ----------
      n : int
          Number of the business day to get.
      gyear : int
          Gregorian year.
      gmonth : int
          Gregorian month.
  
      Returns
      -------
      bizday : int
          Nth business day of a given month in RDate format.
      """
  
      rdate = gdate_to_rdate(gyear, gmonth, 1)
      holidays = set_holidays(gyear, True)
      ibd = 0
      idate = rdate
      while ibd < n:
          dw = day_of_week(idate)
          week_day = dw >= 1 and dw <= 5
          if week_day and idate not in holidays.values():
              ibd += 1
              bizday = idate
          idate += 1
      return bizday
  
imports: import calendar
  import logging
  import math
  import pandas
label_desc: Use image node_id 20 for calling a global function with example usage: nth_bizday(n, gyear, gmonth) and returns: bizday