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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 add_child(self, child, modify=False):
 """ Adds an object as a child in the scene graph. With modify=True, model_matrix_transform gets change from identity and prevents the changes of the coordinates of the child"""

        SceneGraph.add_child(self, child)
        self.notify()
        if modify:
            child._model_matrix_transform[:] = trans.inverse_matrix(self.model_matrix_global)
            child._normal_matrix_transform[:] = trans.inverse_matrix(self.normal_matrix_global)