def _validate_n_sigfig(n_sigfig: int) -> None:
    """
    Validates the input for the number of significant figures.

    Args:
        n_sigfig (int): The number of significant figures to validate.

    Raises:
        ValueError: If the length of `n_sigfig` is not 1, or if the value is `None` or less than 1.
        TypeError: If the input for `n_sigfig` is not an integer.

    Returns:
        None
    """

    # Check that the input `n_sigfig` is a scalar value (not a list or tuple)
    if isinstance(n_sigfig, (list, tuple)):
        raise TypeError("Any input for `n_sigfig` must be a scalar value.")
    # Check that the input `n_sigfig` is not `None`
    if not isinstance(n_sigfig, int):
        raise TypeError("Any input for `n_sigfig` must be an integer.")
    # The value of `n_sigfig` must be greater than or equal to 1
    if n_sigfig < 1:
        raise ValueError("The value for `n_sigfig` must be greater than or equal to `1`.")

    Validates the input for the number of significant figures.

    Args:
        n_sigfig (int): The number of significant figures to validate.

    Raises:
        ValueError: If the length of `n_sigfig` is not 1, or if the value is `None` or less than 1.
        TypeError: If the input for `n_sigfig` is not an integer.

    Returns:
        None
    
great_tables/_formats.py