enum bug repro

openapi.json

{
    "openapi": "3.0.2",
    "info": {
        "title": "My Test API",
        "description": "An API for testing openapi-python-client",
        "version": "0.1.0"
    },
    "paths": {
        "/tests/": {
            "get": {
                "description": "Get a list of things ",
                "operationId": "getUserList",
                "parameters": [
                    {
                        "required": true,
                        "schema": {
                            "title": "An Enum Value",
                            "type": "array",
                            "items": {
                                "$ref": "#/components/schemas/AnEnum"
                            }
                        },
                        "name": "an_enum_value",
                        "in": "query"
                    }
               ],
                "responses": {
                    "200": {
                        "description": "Successful Response"
                    }
                }
            }
        }
    },
    "components": {
        "schemas": {
            "AnEnum": {
                "title": "AnEnum",
                "enum": [
                    "FIRST_VALUE",
                    "SECOND_VALUE",
                    "modifiedAt:desc"
                ],
                "description": "For testing Enums in all the ways they can be used "
            }
        }
    }
}