Wagtail 2: How to limit one page type per site.

yourpage.py

from wagtail.core.models import Page


class YourPage(Page):
    """Your Wagtail Page Type."""
    
    template = "templates/home_page.html"

    @classmethod
    def can_create_at(cls, parent):
        """You can only create one of these."""
        return super().can_create_at(parent) and not cls.objects.exists()