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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_value(self, node, scope, ctxt, stream):
 """Return the value of the node. It is expected to be either an AST.ID instance or a constant :node: TODO :returns: TODO """


        res = self._handle_node(node, scope, ctxt, stream)

        if isinstance(res, fields.Field):
            return res._pfp__value

        # assume it's a constant
        else:
            return res