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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_tunnel_context(self, context_id, **kwargs):
 """Retrieves the network tunnel context instance. :param int context_id: The id-value representing the context instance. :return dict: Mapping of properties for the tunnel context. :raise SoftLayerAPIError: If a context cannot be found. """

        _filter = utils.NestedDict(kwargs.get('filter') or {})
        _filter['networkTunnelContexts']['id'] = utils.query_filter(context_id)

        kwargs['filter'] = _filter.to_dict()
        contexts = self.account.getNetworkTunnelContexts(**kwargs)
        if len(contexts) == 0:
            raise SoftLayerAPIError('SoftLayer_Exception_ObjectNotFound',
                                    'Unable to find object with id of \'{}\''
                                    .format(context_id))
        return contexts[0]