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    'list_count_is' => array(

      'label' => t('List count comparison'),

      'parameter' => array(

        'list' => array(

          'type' => 'list',

          'label' => t('List to check'),

          'description' => t('A multi value data element to have its count compared, specified by using a data selector, eg node:author:roles.'),

        ),

        'op' => array(

          'type' => 'text',

          'label' => t('Operator'),

          'description' => t('The comparison operator.'),

          'optional' => TRUE,

          'default value' => '==',

          'options list' => 'rules_condition_data_list_count_is_operator_options',

          'restriction' => 'input',

        ),

        'value' => array(

          'type' => 'integer',

          'label' => t('Count'),

          'description' => t('The count to compare the data count with.'),

        ),

      ),

      'group' => t('Data'),

      'base' => 'rules_condition_data_list_count_is',

    ),

/**

 * Options list callback for condition list_count_is.

 */

function rules_condition_data_list_count_is_operator_options() {

  return array(

    '==' => t('equals'),

    '<' => t('is lower than'),

    '>' => t('is greater than'),

  );

}