fn impl_class(
    cls: &Ident,
    args: &PyClassArgs,
    doc: PythonDoc,
    field_options: Vec<(&Field, FieldPyO3Options)>,
    methods_type: PyClassMethodsType,
    ctx: &Ctx,
) -> Result<TokenStream>fn impl_class(
    cls: &Ident,
    args: &PyClassArgs,
    doc: PythonDoc,
    field_options: Vec<(&Field, FieldPyO3Options)>,
    methods_type: PyClassMethodsType,
    ctx: &Ctx,
) -> Result<TokenStream>