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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 matrix(self, _):
 """Return translation matrix in homogeneous coordinates."""

        x, y, z = self.coord
        return np.array([
            [1., 0., 0., x],
            [0., 1., 0., y],
            [0., 0., 1., z],
            [0., 0., 0., 1.]
        ])