def METHOD_NAME(self):
    c = self.c
    for p in c.all_positions():
        h = p.h.strip()
        if h.startswith('@slideshow'):
            self.firstSlideShow = p.copy()
            return p
        if g.match_word(h, 0, '@ignore'):
            p = p.nodeAfterTree()
    self.firstSlideShow = None
    return None