diff --git a/classes/badgeinfo.php b/classes/badgeinfo.php
index f5b35f2..5c1834d 100644
--- a/classes/badgeinfo.php
+++ b/classes/badgeinfo.php
@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
 /**
- * Handle badge information 
+ * Handle badge information
  * @package    local_treestudyplan
  * @copyright  2023 P.M. Kuipers
  * @license    https://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
diff --git a/classes/courseinfo.php b/classes/courseinfo.php
index fea7c67..cb97584 100644
--- a/classes/courseinfo.php
+++ b/classes/courseinfo.php
@@ -145,7 +145,7 @@ class courseinfo {
     }
 
     /**
-     * Construct courseinfo based on course id and 
+     * Construct courseinfo based on course id and
      * @param int $id Course id
      * @param studyitem|null $studyitem Studyitem linking this course (if applicable)
      */
@@ -178,7 +178,7 @@ class courseinfo {
         return $DB->get_field(self::TABLE, "id", ['shortname' => $shortname]);
     }
 
-    /** 
+    /**
      * Determine course timing [future, present or past] based on a course date
      * @param stdClass $course Course database record
      * @return string 'future', 'present' or 'past'
@@ -196,7 +196,7 @@ class courseinfo {
         }
     }
 
-    /** 
+    /**
      * Determine course timing for this course [future, present or past]
      * @return string 'future', 'present' or 'past'
      */
@@ -248,7 +248,7 @@ class courseinfo {
         ], 'referenced course information', $value);
     }
 
-     /**
+    /**
      * Webservice model for basic info
      * @return array Webservice data model
      */
diff --git a/classes/period.php b/classes/period.php
index e32fdd3..f3b573f 100644
--- a/classes/period.php
+++ b/classes/period.php
@@ -49,7 +49,7 @@ class period {
     /**
      * Find record in database and return management object
      * @param int $id Id of database record
-     * @return self 
+     * @return self
      */
     public static function find_by_id($id): self {
         if (!array_key_exists($id, self::$cache)) {
diff --git a/classes/studyitem.php b/classes/studyitem.php
index 136958f..f8dd99a 100644
--- a/classes/studyitem.php
+++ b/classes/studyitem.php
@@ -72,7 +72,7 @@ class studyitem {
     /**
      * Find record in database and return management object
      * @param int $id Id of database record
-     * @return self 
+     * @return self
      */
     public static function find_by_id($id): self {
         if (!array_key_exists($id, self::$studyitemcache)) {
@@ -320,8 +320,8 @@ class studyitem {
         global $DB;
 
         foreach ($resequence as $sq) {
-            // Only change line_id if new line is within the same studyplan page
-            if ( studyitem::find_by_id($sq['id'])->studyline()->page()->id() == 
+            // Only change line_id if new line is within the same studyplan page.
+            if ( self::find_by_id($sq['id'])->studyline()->page()->id() ==
                  studyline::find_by_id($sq['line_id'])->page()->id() ) {
                 $DB->update_record(self::TABLE, [
                     'id' => $sq['id'],
diff --git a/classes/studyline.php b/classes/studyline.php
index de1de40..2616b20 100644
--- a/classes/studyline.php
+++ b/classes/studyline.php
@@ -79,7 +79,7 @@ class studyline {
     /**
      * Find record in database and return management object
      * @param int $id Id of database record
-     * @return self 
+     * @return self
      */
     public static function find_by_id($id): self {
         if (!array_key_exists($id, self::$studylinecache)) {
diff --git a/classes/studyplan.php b/classes/studyplan.php
index 3ec054f..e334f80 100644
--- a/classes/studyplan.php
+++ b/classes/studyplan.php
@@ -53,7 +53,7 @@ class studyplan {
     /**
      * Find record in database and return management object
      * @param int $id Id of database record
-     * @return self 
+     * @return self
      */
     public static function find_by_id($id): self {
         if (!array_key_exists($id, self::$studyplancache)) {
@@ -145,7 +145,7 @@ class studyplan {
         ], 'Basic studyplan info', $value);
     }
 
-     /**
+    /**
      * Webservice model for basic info
      * @return array Webservice data model
      */
diff --git a/classes/studyplanpage.php b/classes/studyplanpage.php
index 3be1d30..29156a8 100644
--- a/classes/studyplanpage.php
+++ b/classes/studyplanpage.php
@@ -29,7 +29,7 @@ require_once($CFG->libdir.'/externallib.php');
  */
 class studyplanpage {
 
-    /** 
+    /**
      * Database table this class models for
      * @var string */
     const TABLE = "local_treestudyplan_page";
@@ -42,7 +42,7 @@ class studyplanpage {
      * Holds database record
      * @var stdClass
      */
-    private $r; // Holds database record.
+    private $r;
     /** @var int */
     private $id;
     /** @var studyplan*/
@@ -59,7 +59,7 @@ class studyplanpage {
     /**
      * Find record in database and return management object
      * @param int $id Id of database record
-     * @return self 
+     * @return self
      */
     public static function find_by_id($id): self {
         if (!array_key_exists($id, self::$cache)) {
@@ -157,7 +157,7 @@ class studyplanpage {
         ], 'Studyplan page basic info', $value);
     }
 
-     /**
+    /**
      * Webservice model for basic info
      * @return array Webservice data model
      */
@@ -613,7 +613,7 @@ class studyplanpage {
 
     /**
      * Find a studyline in this page by its shortname
-     * @param string $shortname 
+     * @param string $shortname
      * @return studyline|null
      */
     protected function find_studyline_by_shortname($shortname) {
diff --git a/classes/studyplanservice.php b/classes/studyplanservice.php
index 193cd61..f377ba0 100644
--- a/classes/studyplanservice.php
+++ b/classes/studyplanservice.php
@@ -474,7 +474,7 @@ class studyplanservice extends \external_api {
      * Delete a study line
      * @param mixed $id Id of the studyline
      * @return array Success/fail model
-     * 
+     *
      */
     public static function delete_studyline($id) {
         $o = studyline::find_by_id($id);
@@ -604,7 +604,7 @@ class studyplanservice extends \external_api {
     /**
      * Add a new study item
      * @param int $lineid
-     * @param string $type 
+     * @param string $type
      * @param array $details
      * @param int $slot
      * @param int $layer
@@ -912,7 +912,7 @@ class studyplanservice extends \external_api {
      * @param bool $include Include grade or not
      * @param bool $required Mark grade as required or not
      * @return array Success/Fail model
-     * 
+     *
      */
     public static function include_grade($gradeid, $itemid, $include, $required = false) {
         global $USER;
@@ -1001,7 +1001,7 @@ class studyplanservice extends \external_api {
      * @param int $scaleid Id of scale to use
      * @return array
      */
-        public static function force_studyplan_scale($studyplanid, $scaleid) {
+    public static function force_studyplan_scale($studyplanid, $scaleid) {
         global $DB;
         $dbman = $DB->get_manager();
 
@@ -1262,9 +1262,9 @@ class studyplanservice extends \external_api {
         return studyplan::export_structure();
     }
 
-    
+
     /**
-     * Export studyplan 
+     * Export studyplan
      * @param mixed $studyplanid Id of studyplan to export
      * @param string $format Export format [csv, json (default)]
      * @return array
@@ -1347,7 +1347,7 @@ class studyplanservice extends \external_api {
 
     /**
      * Import studyplan from file
-     * @param string $content Content of file 
+     * @param string $content Content of file
      * @param string $format Format of file
      * @param int $contextid ID of context to import to
      * @return array Success/fail model
@@ -1389,7 +1389,7 @@ class studyplanservice extends \external_api {
     /**
      * Import studylines into existing studtplan
      * @param int $studyplanid ID of studyplan to import to
-     * @param string $content Content of file 
+     * @param string $content Content of file
      * @param string $format Format of file
      * @return array Success/fail model
      */
@@ -1436,7 +1436,7 @@ class studyplanservice extends \external_api {
 
     /**
      * Submit hacked course activity edit form to edit just name and description
-     * @deprecated will remove hacked edit form in the future 
+     * @deprecated will remove hacked edit form in the future
      * @param mixed $cmid
      * @param mixed $formdata
      * @return array Success/fail structure