code: @Override
      public boolean loadValuesFrom(String filename) {
          String propContent = textIn(filename);
          PropertiesHelper propHelper = getEnvironment().getPropertiesHelper();
          Properties properties = propHelper.parsePropertiesString(propContent);
          Map<String, Object> propAsMap = propHelper.convertPropertiesToMap(properties);
          getCurrentValues().putAll(propAsMap);
          return true;
      }
docs: Adds the properties loaded from the specified file to current values.
  
  @param filename .properties file to load
  @return true when file is loaded
  @throws IOException when unable to load file's content.