What about this style of indent?
```python
nav.add_branch(
    'automate_explorer',
    {
        'automate_explorer_add_ns': lambda ctx: nav_add_namespace(ctx['namespace'].path),
        'automate_explorer_edit_ns': lambda ctx: nav_edit_namespace(ctx['namespace'].path),
        'namespace': lambda ctx: nav_new_class(ctx['namespace'].path),
        'class': lambda ctx: nav_edit_namespace(ctx['class'].path)
    })
```
One more line but you can put more things on one line without line break.