def get_bond_from_num(n: int) -> str:
    """Returns the SMILES symbol representing a bond with multiplicity
    ``n``. More specifically, ``'' = 1`` and ``'=' = 2`` and ``'#' = 3``.

    :param n: either 1, 2, 3.
    :return: the SMILES symbol representing a bond with multiplicity ``n``.
    """

    return ('', '=', '#')[n - 1]