def get_lower_bound(self):
        """Compute the lower bound to integrate cumulative density.

        Returns:
            float: lower bound for cumulative density integral.
        """
        lower_bounds = []

        for distribution in self.distribs.values():
            lower_bound = distribution.percent_point(distribution.mean / 10000)
            if not pd.isnull(lower_bound):
                lower_bounds.append(lower_bound)

        return min(lower_bounds)
Compute the lower bound to integrate cumulative density.

        Returns:
            float: lower bound for cumulative density integral.