pwman3/pwman/data/drivers/__init__.py

try:
    from .sqlite import SQLite
except ImportError:
    pass

try:
    from .postgresql import PostgresqlDatabase
except ImportError:
    pass

try:
    from .mysql import MySQLDatabase
except ImportError:
    pass

try:
    from .mongodb import MongoDB
except ImportError:
    pass

_all__ = [SQLite, PostgresqlDatabase, MySQLDatabase, MongoDB]