arg_name: param name: $key type: array|object description: | Specifies the field or fields to index and the index order.
For example, the following specifies a descending index on the ``username`` field:
.. code-block:: php
[ 'username' => -1 ]
interface: phpmethod
operation: ~
optional: false --- source: file: apiargs-common-param.yaml ref: $options
...
