RW_Meta_Box::normalize_fields PHP Method

    public static function normalize_fields($fields)
    {
        foreach ($fields as $k => $field) {
            $field = RWMB_Field::call('normalize', $field);
            // Allow to add default values for fields
            $field = apply_filters('rwmb_normalize_field', $field);
            $field = apply_filters("rwmb_normalize_{$field['type']}_field", $field);
            $field = apply_filters("rwmb_normalize_{$field['id']}_field", $field);
            $fields[$k] = $field;
        }
        return $fields;
    }

 /**
  * Normalize group fields.
  *
  * @param array $field
  *
  * @return array
  */
 public static function normalize($field)
 {
     $field = parent::normalize($field);
     $field['fields'] = RW_Meta_Box::normalize_fields($field['fields']);
     return $field;
 }