diff --git a/advlabdb/modelViews.py b/advlabdb/modelViews.py
index de8762d..7d36548 100644
--- a/advlabdb/modelViews.py
+++ b/advlabdb/modelViews.py
@@ -287,14 +287,7 @@ class GroupView(SecureModelView):
 
     def create_model(self, form):
         try:
-            orderedPartGroups = Group.query.filter(Group.part == form.part.data).order_by(Group.number)
-            lastTakenGroupNumber = orderedPartGroups[-1].number if orderedPartGroups.count() > 0 else 0
-
-            model = Group(
-                number=lastTakenGroupNumber + 1,
-                part_students=form.part_students.data,
-                part=form.part.data,
-            )
+            model = Group.customInit(form.part.data, form.part_students.data)
 
             self.session.add(model)
             self.on_model_change(form, model, True)
@@ -416,35 +409,17 @@ class GroupExperimentView(SecureModelView):
 
     def create_model(self, form):
         try:
-            model = GroupExperiment.checkAndInit(
-                semester_experiment=form.semester_experiment.data, group=form.group.data
-            )
+            model = GroupExperiment.customInit(semester_experiment=form.semester_experiment.data, group=form.group.data)
 
             self.session.add(model)
 
-            for appointmentDate, special, assistant in zip(
+            for date, special, assistant in zip(
                 [form.appointment1_date.data, form.appointment2_date.data],
                 [form.appointment1_special.data, form.appointment2_special.data],
                 [form.appointment1_assistant.data, form.appointment2_assistant.data],
             ):
-                if appointmentDate:
-                    if assistant:
-                        if assistant not in form.semester_experiment.data.assistants:
-                            raise Exception(f"{assistant} not responsible for {form.semester_experiment.data}!")
-                    else:
-                        if len(form.semester_experiment.data.assistants) != 1:
-                            raise Exception(
-                                f"Experiment {form.semester_experiment.data} has more than one assistant. You have to assign one of these assistants: {form.semester_experiment.data.assistants}"
-                            )
-
-                        assistant = form.semester_experiment.data.assistants[0]
-
-                    appointment = Appointment(
-                        date=appointmentDate,
-                        special=special,
-                        group_experiment=model,
-                        assistant=assistant,
-                    )
+                if date:
+                    appointment = Appointment.customInit(date, special, assistant, model)
 
                     self.session.add(appointment)
 
diff --git a/advlabdb/models.py b/advlabdb/models.py
index f141ff0..d34ab8e 100644
--- a/advlabdb/models.py
+++ b/advlabdb/models.py
@@ -69,6 +69,16 @@ class Group(db.Model):
 
     __table_args__ = (db.UniqueConstraint(number, part_id),)
 
+    def customInit(part, partStudents):
+        orderedPartGroups = Group.query.filter(Group.part == part).order_by(Group.number)
+        lastTakenGroupNumber = orderedPartGroups[-1].number if orderedPartGroups.count() > 0 else 0
+
+        return Group(
+            number=lastTakenGroupNumber + 1,
+            part_students=partStudents,
+            part=part,
+        )
+
     def repr(self):
         return f"{self.number} {self.part.repr()}"
 
@@ -86,13 +96,7 @@ class GroupExperiment(db.Model):
 
     __table_args__ = (db.UniqueConstraint(semester_experiment_id, group_id),)
 
-    def repr(self):
-        return f"SemExp {self.semester_experiment.repr()}; Gr {self.group.repr()}"
-
-    def __repr__(self):
-        return f"<GREXP {self.repr()}>"
-
-    def checkAndInit(semester_experiment, group):
+    def customInit(semester_experiment, group):
         for partStudent in group.part_students:
             student = partStudent.student
             for partStudent in student.part_students:
@@ -104,6 +108,12 @@ class GroupExperiment(db.Model):
 
         return GroupExperiment(semester_experiment=semester_experiment, group=group)
 
+    def repr(self):
+        return f"SemExp {self.semester_experiment.repr()}; Gr {self.group.repr()}"
+
+    def __repr__(self):
+        return f"<GREXP {self.repr()}>"
+
 
 class Experiment(db.Model):
     id = db.Column(db.Integer, primary_key=True)
@@ -181,6 +191,31 @@ class Appointment(db.Model):
     group_experiment_id = db.Column(db.Integer, db.ForeignKey("group_experiment.id"), nullable=False)
     assistant_id = db.Column(db.Integer, db.ForeignKey("assistant.id"), nullable=False)
 
+    def customInit(date, special, assistant, groupExperiment):
+        semesterExperiment = groupExperiment.semester_experiment
+        semesterExperimentAssistants = semesterExperiment.assistants
+
+        if not semesterExperimentAssistants:
+            raise Exception(f"{semesterExperiment} has no assistants yet!")
+
+        if assistant:
+            if assistant not in semesterExperimentAssistants:
+                raise Exception(f"{assistant} not responsible for {semesterExperiment}!")
+        else:
+            if len(semesterExperimentAssistants) == 1:
+                assistant = semesterExperimentAssistants[0]
+            else:
+                raise Exception(
+                    f"Experiment {semesterExperiment} has more than one assistant. You have to assign one of these assistants: {semesterExperimentAssistants}"
+                )
+
+        return Appointment(
+            date=date,
+            special=special,
+            group_experiment=groupExperiment,
+            assistant=assistant,
+        )
+
     def repr(self):
         return f"{self.date} {self.group_experiment.repr()}"