This function checks out an object or a whole hiearchie of objects. The parameters array contains the required element 'objectIdentifier' and the optional element 'version', 'mode' and 'objectQuery'. 'mode' can be one of the following values:
Checks out an object. The object must be a document.
If the object to check out is a collection, all children will be checked out recursively if they are documents. Trying to check out a collection would result in an error.
See also hwapi_checkin().