Python Docstrings — Google Style

A docstring earns its place by saying what type hints cannot: meaning, constraints, side effects, and failure conditions. Google style expresses those as indented sections (Args:, Returns:, Raises:) that Sphinx Napoleon compiles into the same field lists reST uses — so write for two readers at once: a human scanning a tooltip and Sphinx rendering API docs.

Canonical shape

async def fetch_one(self, query: str, *args: Any) -> Mapping[str, Any] | None:
    """Executes a query and returns the first matching row.

    Args:
        query (str): SQL query text with numbered placeholders.
        *args (Any): Positional parameters bound to the placeholders.