Drill 20: Inputs and outputs — Forms and validation

from django import forms
from .models import Lesson

class LessonForm(forms.ModelForm):
    class Meta:
        model = Lesson
        fields = ('title', 'minutes', 'published')

    def clean_minutes(self) -> int:
        minutes = self.cleaned_data['minutes']
        if minutes < 1 or minutes > 240:
            raise forms.ValidationError('Minutes must be between 1 and 240.')
        return minutes