def cov_hc0(results):
 het_scale = (results.resid ** 2)
 cov_hc0 = _HCCM(results, het_scale)
 return cov_hc0

def cov_hc0 ( results ) : het_scale = ( results . resid ** 2 ) cov_hc0 = _HCCM ( results , het_scale ) return cov_hc0
see statsmodels .