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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Optional nullable model properties are deserialized from `UNSET` to `None`","articleBody":"**Describe the bug**\r\nIf a model has an optional nullable model property, then in the `from_dict`, if the key is not present in the dictionary, it is deserialized as `None` instead of `UNSET`.\r\n\r\nThis is also true for enum properties, and probably other types as well, but we haven't done an exhaustive search.\r\n\r\n**To Reproduce**\r\nThis can already be seen in `end_to_end_tests/golden-record/my_test_api_client/models/a_model.py:345`, where the deserialized value is initialized to `None`.\r\n\r\n**Expected behavior**\r\n`UNSET` keys should be deserialized as `UNSET`.\r\n\r\n**OpenAPI Spec File**\r\nExisting `openapi.json`\r\n\r\n**Desktop (please complete the following information):**\r\n - OS: [e.g. macOS 10.15.1]\r\n - Python Version: [e.g. 3.8.0]\r\n - openapi-python-client version [e.g. 0.1.0]\r\n\r\n**Additional context**\r\n","author":{"url":"https://github.com/forest-benchling","@type":"Person","name":"forest-benchling"},"datePublished":"2021-04-07T13:54:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/381/openapi-python-client/issues/381"}