Deletes data stored for a user account.
string|array $module: (optional) The name of the module the data is associated with. Can also be an array to delete the data of multiple modules.
integer|array $uid: (optional) The user account ID the data is associated with. If omitted, all data for $module is deleted. Can also be an array of IDs to delete the data of multiple user accounts.
string $name: (optional) The name of the data key. If omitted, all data associated with $module and $uid is deleted.
void
public function delete($module = NULL, $uid = NULL, $name = NULL);