code: def convert_lat(Recs):
      
      New = []
      for rec in Recs:
          if 'model_lat' in list(rec.keys()) and rec['model_lat'] != "":
              New.append(rec)
          elif 'average_age' in list(rec.keys()) and rec['average_age'] != "" and float(rec['average_age']) <= 5.:
              if 'site_lat' in list(rec.keys()) and rec['site_lat'] != "":
                  rec['model_lat'] = rec['site_lat']
                  New.append(rec)
          elif 'average_inc' in list(rec.keys()) and rec['average_inc'] != "":
              rec['model_lat'] = '%7.1f' % (plat(float(rec['average_inc'])))
              New.append(rec)
      return New
docs: uses lat, for age<5Ma, model_lat if present, else tries to use average_inc to estimate plat.