code: def _mmInit(self):
          
          # cache references to speed up loop a bit
          mmkeys = {}
          mmkeysGet = mmkeys.setdefault
          minkeylength = self.minkeylength
          for key in self.data.keys():
              # add abbreviations as short as minkeylength
              # always add at least one entry (even for key="")
              lenkey = len(key)
              start = min(minkeylength,lenkey)
              for i in range(start,lenkey+1):
                  mmkeysGet(key[0:i],[]).append(key)
          self.mmkeys = mmkeys
docs: Create the minimum match dictionary of keys