Can you go into detail why it leads to a circular import?  What are the circular dependencies?  I'd like to see if we can resolve the circular dependency rather than using a decorator.

While this decorator solves the problem, it does it in a way that strikes me as too implicit.  I think something like this would be more explicit; am curious what your thoughts are:

```python
def zeros(..., context=None, ...):
    context = context or WORLD
    ...
```
It's one extra line per function, but it's fairly trivial, as long as we can resolve the circular dependency issue.  And if we can't, then it's just two lines -- one for the import, and one for the assignment.