sqlalchemy and SQLite shared cache

SQLite supports a "shared cache" for :memory: databases when they are opened with a special URI (according to sqlite.org):

[T]he same in-memory database can be opened by two or more database connections as follows:

rc = sqlite3_open("file::memory:?cache=shared",&db);

I can take advantage of this in Python 3.4 by using the URI parameter for sqlite3.connect():

sqlite3.connect('file::memory:?cache=shared', uri=True)

However, I can't seem to get the same thing working for SQLAlchemy:

engine = sqlalchemy.create_engine('sqlite:///:memory:?cache=shared')
engine.connect()
...
TypeError: 'cache' is an invalid keyword argument for this function

Is there some way to get SQLAlchemy to make use of the shared cache?