def is_tepid(G):
    """
    Determine if G is tepid.

    A Game is tepid if it is numberish, but not a number; that is, it differs
    from a number by an infinitesimal amount.

    Parameters
    ----------
    G : Game
        The Game of interest.

    Returns
    -------
    tepid : bool
        Whether the Game is tepid or not.
    """
    return G.is_numberish and not G.is_number