docs: def convert_ages_to_calendar_year(self, er_ages_rec):
          """
          convert all age units to calendar year
  
          Parameters
          ----------
          er_ages_rec : Dict type object containing preferbly at least keys
              'age', 'age_unit', and either 'age_range_high', 'age_range_low'
              or 'age_sigma'
  
          Returns
          -------
          er_ages_rec : Same dict object input but altered to have new records
              'age_cal_year_range_low' and 'age_cal_year_range_high'
          """
          if "age" not in list(er_ages_rec.keys()):
              return(er_ages_rec)
          if "age_unit" not in list(er_ages_rec.keys()):
              return(er_ages_rec)
          if er_ages_rec["age_unit"] == "":
              return(er_ages_rec)
  
          if er_ages_rec["age"] == "":
              if "age_range_high" in list(er_ages_rec.keys()) and "age_range_low" in list(er_ages_rec.keys()):
                  if er_ages_rec["age_range_high"] != "" and er_ages_rec["age_range_low"] != "":
                      er_ages_rec["age"] = scipy.mean(
                          [float(er_ages_rec["age_range_high"]), float(er_ages_rec["age_range_low"])])
          if er_ages_rec["age"] == "":
              return(er_ages_rec)
  
          age_unit = er_ages_rec["age_unit"]
  
          # Fix 'age':
          mutliplier = 1
          if age_unit == "Ga":
              mutliplier = -1e9
          if age_unit == "Ma":
              mutliplier = -1e6
          if age_unit == "Ka":
              mutliplier = -1e3
          if age_unit == "Years AD (+/-)" or age_unit == "Years Cal AD (+/-)":
              mutliplier = 1
          if age_unit == "Years BP" or age_unit == "Years Cal BP":
              mutliplier = 1
          age = float(er_ages_rec["age"])*mutliplier
          if age_unit == "Years BP" or age_unit == "Years Cal BP":
              age = 1950-age
          er_ages_rec['age_cal_year'] = age
  
          # Fix 'age_range_low':
          age_range_low = age
          age_range_high = age
          age_sigma = 0
  
          if "age_sigma" in list(er_ages_rec.keys()) and er_ages_rec["age_sigma"] != "":
              age_sigma = float(er_ages_rec["age_sigma"])*mutliplier
              if age_unit == "Years BP" or age_unit == "Years Cal BP":
                  age_sigma = 1950-age_sigma
              age_range_low = age-age_sigma
              age_range_high = age+age_sigma
  
          if "age_range_high" in list(er_ages_rec.keys()) and "age_range_low" in list(er_ages_rec.keys()):
              if er_ages_rec["age_range_high"] != "" and er_ages_rec["age_range_low"] != "":
                  age_range_high = float(
                      er_ages_rec["age_range_high"])*mutliplier
                  if age_unit == "Years BP" or age_unit == "Years Cal BP":
                      age_range_high = 1950-age_range_high
                  age_range_low = float(er_ages_rec["age_range_low"])*mutliplier
                  if age_unit == "Years BP" or age_unit == "Years Cal BP":
                      age_range_low = 1950-age_range_low
          er_ages_rec['age_cal_year_range_low'] = age_range_low
          er_ages_rec['age_cal_year_range_high'] = age_range_high
  
          return(er_ages_rec)