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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 describe_instances(self, *instance_ids):
 """Describe current instances."""

        instances = {}
        for pos, instance_id in enumerate(instance_ids):
            instances["InstanceId.%d" % (pos + 1)] = instance_id
        query = self.query_factory(
            action="DescribeInstances", creds=self.creds,
            endpoint=self.endpoint, other_params=instances)
        d = query.submit()
        return d.addCallback(self.parser.describe_instances)