code: def delete_property(self, prop):
          
          if _debug: Object._debug("delete_property %r", prop)
  
          # make a copy of the properties dictionary
          self._properties = _copy(self._properties)
  
          # delete the property from the dictionary and values
          del self._properties[prop.identifier]
          if prop.identifier in self._values:
              del self._values[prop.identifier]
docs: Delete a property from an object.  The property is an instance of
          a Property or one of its derived classes, but only the property
          is relavent.  Deleting a property disconnects it from the collection of
          properties common to all of the objects of its class.