Failing import with newer version of sqlalchemy

[jachymb]

When I try to call from aiopg.sa import create_engine I get an error like this: ModuleNotFoundError: No module named 'sqlalchemy.sql.ddl'. It is caused by the from sqlalchemy.sql.ddl import DDLElement command in connection.py.

I believe it should do the following instead for newer versions of sqlalchemy:

from sqlalchemy.schema import DDLElement

[jachymb]

To clarify, the error occurs with sqlalchemy >= 1.3, but not with sqlalchemy 1.2