code: def _convertPyval(self, oself, pyval):
          
          # convert to dbval later, I guess?
          if pyval is None and not self.allowNone:
              raise TypeError("attribute [%s.%s = %s()] must not be None" % (
                      self.classname, self.attrname, self.__class__.__name__))
  
          return self.infilter(pyval, oself, oself.store)
docs: Convert a Python value to a value suitable for inserting into the
          database.
  
          @param oself: The object on which this descriptor is an attribute.
          @param pyval: The value to be converted.
          @return: A value legal for this column in the database.