def cov_hc3(results):
 h = np.diag(np.dot(results.model.exog, np.dot(results.normalized_cov_params, results.model.exog.T)))
 het_scale = ((results.resid / (1 - h)) ** 2)
 cov_hc3_ = _HCCM(results, het_scale)
 return cov_hc3_

def cov_hc3 ( results ) : h = np . diag ( np . dot ( results . model . exog , np . dot ( results . normalized_cov_params , results . model . exog . T ) ) ) het_scale = ( ( results . resid / ( 1 - h ) ) ** 2 ) cov_hc3_ = _HCCM ( results , het_scale ) return cov_hc3_
see statsmodels .