- remove unused import
- use snake_case instead of camelCase
- add two empty lines between module-level definitions
- rename 'elt' variable to 'element'
- don't make extra dict copy in _load_axis
According to https://github.com/LettError/designSpaceDocument
> Not all values might be required by all applications.
So if any of 'elements', 'sources' or 'instances' is missing, the dictionary
returned by designspace.load will not contain those keys.