from typing import Protocol

class BookingRepository(Protocol):
    """Persistence interface used by scheduling and confirmation."""

    @property
    def technicians(self) -> dict[str, Technician]:
        """Return technicians keyed by id."""

    def list_bookings(self) -> list[Booking]:
        """Return all confirmed bookings."""

    def create_booking(
        self, option: TimeOption, details: BookingDetails, price: float
    ) -> Booking:
        """Persist a booking after re-checking overlap; raise ValueError if taken."""