{
  "approach": "Read the read_black_config function to understand how it handles the result from find_pyproject_toml, then determine the minimal fix.",
  "files_to_edit": [
    "lib/python/pyflyby/_importstmt.py"
  ],
  "finish_reason": "stop",
  "hypothesis": "read_black_config calls parse_pyproject_toml from black.files which tries to open a path from the pyproject.toml search. The test mocks find_pyproject_toml to return None, but read_black_config likely passes that None to parse_pyproject_toml which then fails. I need to check the implementation of read_black_config to see how it handles the None result from find_pyproject_toml.",
  "retries": {},
  "usage": {
    "completion": 154,
    "prompt": 5735,
    "reasoning": 0
  }
}