docs: def _create_unicode_map():
      """
      Create the inverse map from unicode to betacode.
  
      Returns:
      The hash map to convert unicode characters to the beta code representation.
      """
      unicode_map = {}
  
      for beta, uni in _map.BETACODE_MAP.items():
          # Include decomposed equivalent where necessary.
          norm = unicodedata.normalize('NFC', uni)
          unicode_map[norm] = beta
          unicode_map[uni] = beta
  
      # Add the final sigmas.
      final_sigma_norm = unicodedata.normalize('NFC', _FINAL_LC_SIGMA)
      unicode_map[final_sigma_norm] = 's'
      unicode_map[_FINAL_LC_SIGMA] = 's'
  
      return unicode_map