code: def convert_all(folder, dest_path='.', force_all=False):
      "Convert modified notebooks in `folder` to html pages in `dest_path`."
      path = Path(folder)
  
      changed_cnt = 0
      for fname in path.glob("*.ipynb"):
          # only rebuild modified files
          fname_out = Path(dest_path)/fname.with_suffix('.html').name
          if not force_all and fname_out.exists():
              in_mod  = os.path.getmtime(fname)
              out_mod = os.path.getmtime(fname_out)
              if in_mod < out_mod: continue
  
          print(f"converting: {fname} => {fname_out}")
          changed_cnt += 1
          convert_nb(fname, dest_path=dest_path)
      if not changed_cnt: print("No notebooks were modified"f convert_all(folder, dest_path='.', force_all=False):
      "Convert modified notebooks in `folder` to html pages in `dest_path`."
      path = Path(folder)
  
      changed_cnt = 0
      for fname in path.glob("*.ipynb"):
          # only rebuild modified files
          fname_out = Path(dest_path)/fname.with_suffix('.html').name
          if not force_all and fname_out.exists():
              in_mod  = os.path.getmtime(fname)
              out_mod = os.path.getmtime(fname_out)
              if in_mod < out_mod: continue
  
          print(f"converting: {fname} => {fname_out}")
          changed_cnt += 1
          convert_nb(fname, dest_path=dest_path)
      if not changed_cnt: print("No notebooks were modified")
docs: Convert modified notebooks in `folder` to html pages in `dest_path`.