docs: def update(self):
          """persist the .fields using .fields_where"""
          self.default_val = 0
          #fields = self.fields
          #fields = self.orm_class.depart(self.fields, is_update=True)
          #self.set_fields(fields)
          return self.interface.update(
              self.schema,
              self.fields,
              self
          )