code: def update_collaboration(self):
          
          for field in record_get_field_instances(self.record, '710'):
              subs = field_get_subfield_instances(field)
              for idx, (key, value) in enumerate(subs[:]):
                  if key == '5':
                      subs.pop(idx)
                  elif value.startswith('CERN. Geneva'):
                      subs.pop(idx)
              if len(subs) == 0:
                  record_delete_field(self.record,
                                      tag='710',
                                      field_position_global=field[4])
docs: 710 Collaboration.