def _is_package_installed(package_name: str) -> bool:
    """
    Checks if a Python package is installed.

    Args:
        package_name: The name of the package to check (e.g., "requests", "numpy").

    Returns:
        True if the package is installed, False otherwise.
    """
    try:
        importlib.import_module(package_name)
        return True
    except Exception:
        return False

    Checks if a Python package is installed.

    Args:
        package_name: The name of the package to check (e.g., "requests", "numpy").

    Returns:
        True if the package is installed, False otherwise.
    
pandas_gbq/environment.py