code: def amax_files():
      
      return [os.path.join(dp, f) for dp, dn, filenames in os.walk(CACHE_FOLDER)
              for f in filenames if os.path.splitext(f)[1].lower() == '.am']
docs: Return all annual maximum flow (`*.am`) files in cache folder and sub folders.
  
      :return: List of file paths
      :rtype: list