code: def _scalar_property(fieldname):
      
  
      def _getter(self):
          """Scalar property getter."""
          return self._properties.get(fieldname)
  
      def _setter(self, value):
          """Scalar property setter."""
          self._patch_property(fieldname, value)
  
      return property(_getter, _setter)
docs: Create a property descriptor around the :class:`_PropertyMixin` helpers.