def cut_down_index(self, bottom, top):
### not fully implemented for non-bibles
vk1 = VK((self.bookname, self.bookname))
vk = VK((bottom, top))
vk_dn = vk.LowerBound()
vk_up = vk.UpperBound()
# the item we are currently looking for
start_ref = None
ret = []
items = []
self.old_text = self.text
self.old_index = self.index
for match in re.finditer("(?m)^.*$", self.text):
if vk_dn <= vk1 <= vk_up:
items.append(match.group())
vk1.increment(1)
self.text = '\n'.join(items)
self.create_index_against_text(vk)
