Rationale =========
A frozendict mapping cannot be changed, but its values can be mutable (not hashable). A frozendict is hashable and so immutable if all values are hashable (immutable). The wording of the above seems very unclear to me.
Do you mean "A frozendict has a constant set of keys, and for every key, d[key] has a specific value for the lifetime of the frozendict. However, these values *may* be mutable. The frozendict is hashable iff all of the values are hashable." ? (or somesuch)
New try: "A frozendict is a read-only mapping: a key cannot be added nor removed, and a key is always mapped to the same value. However, frozendict values can be mutable (not hashable). A frozendict is hashable and so immutable if and only if all values are hashable (immutable)."
* Register frozendict has a collections.abc.Mapping s/has/as/ ?
Oops, fixed.
If frozendict is used to harden Python (security purpose), it must be implemented in C. A type implemented in C is also faster.
You mention security purposes here, but this isn't mentioned in the Rationale or Use Cases
I added two use cases: security sandbox and cache.
Hope this is helpful
Yes, thanks. Victor