/**
  * This function creates a table cell style using the style as set in the assoziative array $properties.
  * The parameters in the array should be named as the CSS property names e.g. 'color' or 'background-color'.
  * Properties which shall not be used in the style can be disabled by setting the value in disabled_props
  * to 1 e.g. $disabled_props ['color'] = 1 would block the usage of the color property.
  *
  * The currently supported properties are:
  * background-color, vertical-align
  *
  * The function returns the name of the new style or NULL if all relevant properties are empty.
  *
  * @author LarsDW223
  * @param $properties
  * @param null $disabled_props
  * @return ODTTableCellStyle or NULL
  */
 public static function createTableCellStyle(array $properties, array $disabled_props = NULL)
 {
     // Create style name (if not given).
     $style_name = $properties['style-name'];
     if (empty($style_name)) {
         $style_name = self::getNewStylename('TableCell');
         $properties['style-name'] = $style_name;
     }
     // Create empty table cell style.
     $object = new ODTTableCellStyle();
     if ($object == NULL) {
         return NULL;
     }
     // Import our properties
     $object->importProperties($properties, $disabled_props);
     return $object;
 }