code: def _remove_ipynb_files(path, contents):
      
      contents_return = []
      for entry in contents:
          if entry.endswith('.ipynb'):
              # Don't include ipynb files
              pass
          elif (entry != "images") and os.path.isdir(os.path.join(path, entry)):
              # Don't include folders not called "images"
              pass
          else:
              # Keep everything else
              contents_return.append(entry)
      return contents_return
docs: Given a list of files in `contents`, remove all files named `ipynb` or
      directories named `images` and return the result.
  
      Used with the `shutil` "ignore" keyword to filter out non-ipynb files.