In order to be added into sets or used as dict keys, Lang instances
must be hashable. As the hash of a Lang instance needs to be
predictable and as the mutability of Lang is not an important feature,
Lang is now immutable.
New feature:
Lang instances are now sortable alphabetically by name.
ISO 639-3 types and scopes are now supported
an iterator through all Lang instances is now included
Bug fixes:
Not just invalid strings but any invalid argument passed to Lang
raises an InvalidLanguageValue exception.
As long as they are compatible, positional and keyword arguments can
be passed to Lang together.
Breaking change:
New feature:
Bug fixes: