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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 mutate(self, node, index):
 """Modify the numeric value on `node`."""


        assert index < len(OFFSETS), 'received count with no associated offset'
        assert isinstance(node, parso.python.tree.Number)

        val = eval(node.value) + OFFSETS[index]  # pylint: disable=W0123
        return parso.python.tree.Number(' ' + str(val), node.start_pos)