The current implementation still has a set_current method https://github.com/open-telemetry/opentelemetry-python/blob/master/opentelemetry-api/src/opentelemetry/context/__init__.py#L101, this was removed from the spec in favour of attach/detach.

As per the spec: https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/context.md#attach-context