{
    "task_id": "memory_leak_medium_1",
    "task_name": "File Handle Leak",
    "description": "Find the memory leak where file handles are not properly closed",
    "difficulty": "medium",
    "code_diff": "def read_files(file_list):\n    contents = []\n    for filename in file_list:\n        f = open(filename, 'r')\n        data = f.read()\n        contents.append(data)\n    return contents",
    "expected_issues": [
        {
            "line": 4,
            "type": "resource_leak",
            "severity": "high",
            "description": "File not closed after reading"
        }
    ]
}