Scheduler (plugin)

But if I manually sending invitations or reminders to students who did not yet make an appointment, I got this error from moodle:

ERROR from moodle:

Error: Argument 2 passed to scheduler_message_form::__construct() must be an instance of scheduler_instance, instance of mod_scheduler\model\scheduler given, called in [dirrot]/mod/scheduler/teacherview.php on line 354

Debug info:
Error code: generalexceptionmessage

Stack trace:
line 37 of /mod/scheduler/message_form.php: Type Error thrown
line 354 of /mod/scheduler/teacherview.php: call to scheduler_message_from->__construct()
line 75 of /mod/scheduler/view.php: call to include()

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Here is what I found at the .php´s:

line 37 message_form.php -->
37: public function __construct($action, scheduler $scheduler, $customdata=null) {
38:   $this->scheduler = $scheduler;
39:   parent::__construct($action, $customdata);
40: }

line 354 teacherview.php -->
354: $mform = new scheduler_message_form($actionurl, $scheduler, $templatedata);

line 75 view.php -->
75: include($CFG->dirroot.'/mod/scheduler/teacherview.php');

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