Either appends or resets the <mustInclude> list of snode_current
            depending on <ab_reset>.

def node_mustInclude(self, al_mustInclude, ab_reset=False):
            """
            Either appends or resets the <mustInclude> list of snode_current
            depending on <ab_reset>.
            """
            if ab_reset:
                self.snode_current.l_mustInclude = al_mustInclude[:]
            else:
                l_current   = self.snode_current.l_mustInclude[:]
                l_total     = l_current + al_mustInclude
                self.snode_current.l_mustInclude = l_total[:]