def cov_hc1(results):
 het_scale = ((results.nobs / results.df_resid) * (results.resid ** 2))
 cov_hc1 = _HCCM(results, het_scale)
 return cov_hc1

def cov_hc1 ( results ) : het_scale = ( ( results . nobs / results . df_resid ) * ( results . resid ** 2 ) ) cov_hc1 = _HCCM ( results , het_scale ) return cov_hc1
see statsmodels .