code: private static String getProperty(String driverId, String propertyName) {
  		String propertyValue = PROPERTIES.getProperty(DEFAULT_PREFIX + "." + driverId + "." + propertyName);
  		if (propertyValue != null) {
  			propertyValue = propertyValue.trim();
  			if (propertyValue.isEmpty()) {
  				propertyValue = null;
  			}
  		}
  		return propertyValue;
  	}
docs: Gets value of the specified property.
  
  @param driverId Driver Id
  @param propertyName Property name
  @return property value or {@code null}