Method cancel

src/trio/_core/_run.py:937–953

Cancels this scope immediately. The optional ``reason`` argument accepts a string, which will be attached to any resulting :exc:`Cancelled` exception to help you understand where that cancellation is coming from and why it happened. This method is idempotent, i.e.,

(self, reason: str | None = None)

    @enable_ki_protection
    def cancel(self, reason: str | None = None) -> None:
        """Cancels this scope immediately.

        The optional ``reason`` argument accepts a string, which will be attached to
        any resulting :exc:`Cancelled` exception to help you understand where that
        cancellation is coming from and why it happened.

        This method is idempotent, i.e., if the scope was already
        cancelled then this method silently does nothing.
        """
        try:
            current_task = repr(_core.current_task())
        except RuntimeError:
            current_task = None
        self._cancel(
            CancelReason(reason=reason, source="explicit", source_task=current_task)
        )

    @property
    def cancel_called(self) -> bool: