def cancel(flavour)

      return reply_to_parent(h.applied_workitem) if h.children.empty?
        #
        # there are no children, nothing to cancel, let's just reply to
        # the parent expression

      do_persist || return
        #
        # before firing the cancel message to the children
        #
        # if the do_persist returns false, it means it failed, implying this
        # expression is stale, let's return, thus discarding this cancel message

      children.each do |child_fei|
        #
        # let's send a cancel message to each of the children
        #
        # maybe some of them are gone or have not yet been applied, anyway,
        # the messages are sent

        @context.storage.put_msg(
          'cancel',
          'fei' => child_fei,
          'parent_id' => h.fei, # indicating that this is a "cancel child"
          'flavour' => flavour)
      end
    end
def cancel(flavour)

      return reply_to_parent(h.applied_workitem) if h.children.empty?
        #
        # there are no children, nothing to cancel, let's just reply to
        # the parent expression

      do_persist || return
        #
        # before firing the cancel message to the children
        #
        # if the do_persist returns false, it means it failed, implying this
        # expression is stale, let's return, thus discarding this cancel message

      children.each do |child_fei|
        #
        # let's send a cancel message to each of the children
        #
        # maybe some of them are gone or have not yet been applied, anyway,
        # the messages are sent

        @context.storage.put_msg(
          'cancel',
          'fei' => child_fei,
          'parent_id' => h.fei, # indicating that this is a "cancel child"
          'flavour' => flavour)
      end
    end
This default implementation cancels all the [registered] children
 of this expression.