def cov(self):
        mu = self.mean()  #JP: call to method (confusing name)
        dx = mu - self.x#np.multiply.outer(mu, self.x.shape[1])
        return np.dot(dx, np.transpose(dx))
##        if dx.ndim == 1:
##            dx = dx[:,None]
##        return np.dot(dx.T, dx)
dataset/ETHPy150Open statsmodels/statsmodels/statsmodels/sandbox/cox.py/Discrete.cov/swapped operands of `-`