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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 _get_grad_method(self, data):
 r"""Get the gradient This method calculates the gradient step from the input data Parameters data : np.ndarray Input data array Notes ----- Implements the following equation: .. math:: \nabla F(x) = \mathbf{H}^T(\mathbf{H}\mathbf{x} - \mathbf{y}) """


        self.grad = self.trans_op(self.op(data) - self.obs_data)