code: def wantFile(self, filename):
          
  
          log.info("considering %s", filename)
  
          if self.testMatch(filename) is None:
              return False
  
          nb = self.readnb(filename)
  
          for cell in self.codeCells(nb):
              return True
  
          log.info("no `code` cells in %s", filename)
  
          return False
docs: filter files to those that match nosebook-match