code: def prev(self, *e):
      selection = self._readingList.curselection()
      readingListSize = self._readingList.size()
  
      # there are readings
      if readingListSize > 0:
          # if one reading is currently selected
          if len(selection) == 1:
              index = int(selection[0])
  
              # if it's on (or before) the first item
              if index <= 0:
                  self._select_previous_example()
              else:
                  self._readingList_store_selection(index - 1)
  
          else:
              # select its first reading
              self._readingList_store_selection(readingListSize - 1)
  
      else:
          self._select_previous_example()
  
imports: from nltk.parse import MaltParser
  from nltk.sem.drt import DrsDrawer, DrtVariableExpression
  from nltk.sem.glue import DrtGlue
  from nltk.sem.logic import Variable
  from nltk.tag import RegexpTagger
  from nltk.util import in_idle
label_desc: Use image node_id 14 for calling the DrtGlueDemo obj's underlying member method code with example usage: obj.prev() without return types