docs: def store(self, thing):
          """
          Simple persistence method
          """
          to_store = {'field1': thing.field1,
                      'date_field': thing.date_field,
                      }
          to_store['stuff'] = Binary(cPickle.dumps(thing.stuff))
          # Respect any soft-quota on write - raises if stats().totals.size > quota 
          self._arctic_lib.check_quota()
          self._collection.insert_one(to_store)