Function remove

lib/sqlalchemy/event/api.py:171–214

Remove an event listener. The arguments here should match exactly those which were sent to :func:`.listen`; all the event registration which proceeded as a result of this call will be reverted by calling :func:`.remove` with the same arguments. e.g.:: # if a function w

(target: Any, identifier: str, fn: Callable[..., Any])

def remove(target: Any, identifier: str, fn: Callable[..., Any]) -> None:
    """Remove an event listener.

    The arguments here should match exactly those which were sent to
    :func:`.listen`; all the event registration which proceeded as a result
    of this call will be reverted by calling :func:`.remove` with the same
    arguments.

    e.g.::

        # if a function was registered like this...
        @event.listens_for(SomeMappedClass, "before_insert", propagate=True)
        def my_listener_function(*arg):
            pass


        # ... it's removed like this
        event.remove(SomeMappedClass, "before_insert", my_listener_function)

    Above, the listener function associated with ``SomeMappedClass`` was also
    propagated to subclasses of ``SomeMappedClass``; the :func:`.remove`
    function will revert all of these operations.

    .. note::

        The :func:`.remove` function cannot be called at the same time
        that the target event is being run.   This has implications
        for thread safety, and also means an event cannot be removed
        from inside the listener function for itself.  The list of
        events to be run are present inside of a mutable collection
        that can't be changed during iteration.

        Event registration and removal is not intended to be a "high
        velocity" operation; it is a configurational operation.  For
        systems that need to quickly associate and deassociate with
        events at high scale, use a mutable structure that is handled
        from inside of a single listener.

    .. seealso::

        :func:`.listen`

    """
    _event_key(target, identifier, fn).remove()


def contains(target: Any, identifier: str, fn: Callable[..., Any]) -> bool: