Attribute failures from 'is_used' property

[robinklaassen]

There is something seriously wrong with the below code in Base, all our use of pycgmes is failing after #38. Still investigating further.

    @staticmethod
    def get_extra_prop(field: Field, prop: str) -> Any:
        # The field is defined as a pydantic field, not a dataclass field,
        # so access to metadata is a tad different. Furthermore, pyright is confused by extra.
>       return field.default.json_schema_extra[prop]  # pyright: ignore[reportAttributeAccessIssue]
E       KeyError: 'is_used'

[tom-hg57]

Do you use custom classes?

In all generated classes json_schema_extra is extended by "is_used", "is_class_attribute", "is_enum_attribute", "is_list_attribute", "is_primitive_attribute". If you use custom classes you have to extend them, too. See e.g. examples/custom_attributes.py or the custom unit tests.

[tom-hg57]

I updated the examples for custom attributes, profiles, and namespaces in README.md in PR #41.

Or does this issue have nothing to do with custom classes?