change in import handling / modules from python2 to python3?

Question

I was trying to following the design pattern shown in this previous question related to SQLAlchemy and intended to share a common Base instance across multiple files. The co

Answer 1

Python 3 switches to absolute imports by default, and disallows unqualified relative imports. The from base import Base line is such an import.

Python 3 will only look for top-level modules; you don't have a base top-level module, only model.base. Use a full module path, or use relative qualifiers:

from .base import Base

The . at the start tells Python 3 to import starting from the current package.

You can enable the same behaviour in Python 2 by adding:

from __future__ import absolute_import

This is a change introduced by PEP 328, and the from future import is available from Python 2.5 onwards.