TypeError when removing a connection event

[Laurence Rowe]

When removing a connection event:

from sqlalchemy import create_engine
from sqlalchemy import event

engine = create_engine('sqlite:///')
connection = engine.connect()

@event.listens_for(connection, 'after_cursor_execute')
def after_cursor_execute(conn, cursor, statement, parameters, context, executemany):
    pass

event.remove(connection, 'after_cursor_execute', after_cursor_execute)

I see the following error:

$ bin/py connection_event_bug.py 
Traceback (most recent call last):
  File "bin/py", line 61, in <module>
    exec(compile(__file__f.read(), __file__, "exec"))
  File "connection_event_bug.py", line 12, in <module>
    event.remove(connection, 'after_cursor_execute', after_cursor_execute)
  File "/Users/lrowe/.buildout/eggs/SQLAlchemy-0.8.0-py2.7-macosx-10.6-intel.egg/sqlalchemy/event.py", line 76, in remove
    for tgt in evt_cls._accept_with(target):
TypeError: 'Connection' object is not iterable

Though this does work:

connection.dispatch.after_cursor_execute.remove(after_cursor_execute, connection)

[Mike Bayer]

yeah, removal of events is basically a TODO at this point - we do it within some of our tests but we do it by clearing out the dispatch dictionaries entirely. removal is in some cases less than trivial due to the way events propagate to related objects; we'd have to locate all those propagated locations as well when an event is removed. #2268 exists as the ticket for this particular task.