'Returns the confidence interval of the fitted parameters.
Parameters
alpha : float, optional
The `alpha` level for the confidence interval.
ie., The default `alpha` = .05 returns a 95% confidence interval.
cols : array-like, optional
`cols` specifies which confidence intervals to return
Notes
The confidence interval is based on Student\'s t-distribution.'

def conf_int(self, alpha=0.05, cols=None):

    ci = super(RegressionResults, self).conf_int(alpha=alpha, cols=cols)
    return ci
