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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def cross_variance(self, x, z, sigmas_f, sigmas_h):
 """ Compute cross variance of the state `x` and measurement `z`. """


        Pxz = zeros((sigmas_f.shape[1], sigmas_h.shape[1]))
        N = sigmas_f.shape[0]
        for i in range(N):
            dx = self.residual_x(sigmas_f[i], x)
            dz = self.residual_z(sigmas_h[i], z)
            Pxz += self.Wc[i] * outer(dx, dz)
        return Pxz