docs: def update(self):
          """re-persist the updated field values of this orm that has a primary key"""
          ret = True
          fields = self.depopulate(True)
          q = self.query
          q.set_fields(fields)
  
          pk = self.pk
          if pk:
              q.is_field(self.schema.pk.name, pk)
  
          else:
              raise ValueError("You cannot update without a primary key")
  
          if q.update():
              fields = q.fields
              self._populate(fields)
  
          else:
              ret = False
  
          return ret