Problem: Accessing a non-existing consumer group offsets causes a segmentation fault.

Steps to Reproduce:

group = ConsumerGroupTopicPartitions(group_id = "non-existing-group")
kafkaAdmin.list_consumer_group_offsets([group])["not-existing-group"].result()

Expected Behavior:
This should throw an exception (like KafkaException or KeyError), not cause a segmentation fault.

Actual Behavior:
A segmentation fault occurs when trying to access a non-existing consumer group.

Version: confluent-kafka-python 2.10.0