@staticmethod
def k_safety(n):
    """
        Vertica defines k-safety values of 0, 1 or 2:
        https://my.vertica.com/docs/7.1.x/HTML/Content/Authoring/Glossary/
        K-Safety.htm
        """
    if n < 3:
        return 0
    elif n < 5:
        return 1
    else:
        return 2
