Dispatch handling of this event to a receiver.

        This method will invoke ``receiver._document_patched`` if it exists.

def dispatch(self, receiver):
        ''' Dispatch handling of this event to a receiver.

        This method will invoke ``receiver._document_patched`` if it exists.

        '''
        super(DocumentPatchedEvent, self).dispatch(receiver)
        if hasattr(receiver, '_document_patched'):
            receiver._document_patched(self)