docs: def convert_ages(Recs, data_model=3):
      """
      converts ages to Ma
      Parameters
      _________
      Recs : list of dictionaries in data model by data_model
      data_model : MagIC data model (default is 3)
      """
      if data_model == 3:
          site_key = 'site'
          agekey = "age"
          keybase = ""
      else:
          site_key = 'er_site_names'
          agekey = find('age', list(rec.keys()))
          if agekey != "":
              keybase = agekey.split('_')[0] + '_'
  
      New = []
      for rec in Recs:
          age = ''
          if rec[keybase + 'age'] != "":
              age = float(rec[keybase + "age"])
          elif rec[keybase + 'age_low'] != "" and rec[keybase + 'age_high'] != '':
              age = np.mean([rec[keybase + 'age_high'],
                             rec[keybase + "age_low"]])
              # age = float(rec[keybase + 'age_low']) + old_div(
              #    (float(rec[keybase + 'age_high']) - float(rec[keybase + 'age_low'])), 2.)
          if age != '':
              rec[keybase + 'age_unit']
              if rec[keybase + 'age_unit'] == 'Ma':
                  rec[keybase + 'age'] = '%10.4e' % (age)
              elif rec[keybase + 'age_unit'] == 'ka' or rec[keybase + 'age_unit'] == 'Ka':
                  rec[keybase + 'age'] = '%10.4e' % (age * .001)
              elif rec[keybase + 'age_unit'] == 'Years AD (+/-)':
                  rec[keybase + 'age'] = '%10.4e' % ((2011 - age) * 1e-6)
              elif rec[keybase + 'age_unit'] == 'Years BP':
                  rec[keybase + 'age'] = '%10.4e' % ((age) * 1e-6)
              rec[keybase + 'age_unit'] = 'Ma'
              New.append(rec)
          else:
              if 'site_key' in list(rec.keys()):
                  print('problem in convert_ages:', rec['site_key'])
              elif 'er_site_name' in list(rec.keys()):
                  print('problem in convert_ages:', rec['site_key'])
              else:
                  print('problem in convert_ages:', rec)
          if len(New) == 0:
              print('no age key:', rec)
      return New