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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 is_instance_running(self, instance_id):
 """Check whether the instance is up and running. :param str instance_id: instance identifier :reutrn: True if instance is running, False otherwise """

        items = self.list_instances(filter=('name eq "%s"' % instance_id))
        for item in items:
            if item['status'] == 'RUNNING':
                return True
        return False