import warnings


def sig_stars(p):
    """Return a R-style significance string corresponding to p values.

    DEPRECATED: will be removed in a future version.

    """
    msg = "This function is deprecated and will be removed in a future version"
    warnings.warn(msg)

    if p < 0.001:
        return "***"
    elif p < 0.01:
        return "**"
    elif p < 0.05:
        return "*"
    elif p < 0.1:
        return "."
    return ""