#348 is tackling validation for attribute values, of which list is one of them. However, lists can be mutated as long as someone has a handle, so one could potentially misuse the Span api by mutating lists afterward.

The purpose of adding validation during the setting of span attributes was to remove the need to perform such validations in the exporters themselves.

Should we freeze lists as they come in? or should we potentially just allow tuples rather than lists as attribute values?