code: public static Properties cleanupProperties(final Properties rawProperties) {
          final Map<String, String> map = cleanupProperties(
                  convertToMap(rawProperties), null);
          return convertToProperties(map);
      }
docs: Any properties which are not well known (i.e. in
  {@link BasicLTIConstants#validPropertyNames}) will be mapped to custom
  properties per the specified semantics.
  
  @deprecated See {@link #cleanupProperties(Map)}
  @param rawProperties A set of {@link Properties} that will be cleaned.
  Keys must be of type {@link String}.
  @return A cleansed version of {@link Properties}.