code: def observe_scanner(self, scanner):
          
          scanner.observe(scanner.ALL_EVENTS,
                          self.absorb_args(self.modules.restore))
          if self.clear:
              scanner.observe(scanner.ALL_EVENTS,
                              self.absorb_args(self.clear_on_run))
          scanner.observe(scanner.ALL_EVENTS, self.absorb_args(self._run))
          if self.debug:
              scanner.observe('created',  echo("callback - created  %(file)s"))
              scanner.observe('modified', echo("callback - changed  %(file)s"))
              scanner.observe('deleted',  echo("callback - deleted  %(file)s"))
          self._scanners.append(scanner)
docs: Hooks into multiple events of a scanner.