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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 _error_dm(self, m, dm, s):
 """Error function. Once self.goal has been defined, compute the error of input using the generalized forward model. """

        pred = self.fmodel.predict_given_context(np.hstack((m, dm)), s, range(len(s)))
        err_v  = pred - self.goal
        error = sum(e*e for e in err_v)
        return error