code: function (value, options, callback) {
              if (!value.length) {
                  return callback(); // avoids empty string or array
              }
  
              if (Array.isArray(value) && value.length === 1) {
                  return callback(null, value[0]); // avoids using multipleIdOrName strategy for a single item array
              }
  
              callback(null, value);
          }
docs: Helper function to sanitize folder option.
  
  @param {String[]|String} value - The list of folders to execute
  @param {Object} options - The set of wrapped options.
  @param {Function} callback - The callback function invoked to mark the end of the folder load routine.
  @returns {*}