docs: def convert_ages_to_calendar_year(self, er_ages_rec):
          '''
          convert all age units to calendar year
          '''
          if ("age" not in list(er_ages_rec.keys())) or (cb.is_null(er_ages_rec['age'], False)):
              return(er_ages_rec)
          if ("age_unit" not in list(er_ages_rec.keys())) or (cb.is_null(er_ages_rec['age_unit'])):
              return(er_ages_rec)
          if cb.is_null(er_ages_rec["age"], False):
              if "age_range_high" in list(er_ages_rec.keys()) and "age_range_low" in list(er_ages_rec.keys()):
                  if cb.not_null(er_ages_rec["age_range_high"], False) and cb.not_null(er_ages_rec["age_range_low"], False):
                      er_ages_rec["age"] = np.mean(
                          [float(er_ages_rec["age_range_high"]), float(er_ages_rec["age_range_low"])])
          if cb.is_null(er_ages_rec["age"], False):
              return(er_ages_rec)
  
              # age_descriptier_ages_recon=er_ages_rec["age_description"]
  
          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 cb.not_null(er_ages_rec["age_sigma"], False):
              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 cb.not_null(er_ages_rec["age_range_high"], False) and cb.not_null(er_ages_rec["age_range_low"], False):
                  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)