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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_eni_id(self, interface=1):
 """Given an interface number, gets the AWS elastic network interface associated with the interface. :param interface: Integer associated to the interface/device number :return: String Elastic Network Interface ID or None if not found :raises OSError, AWSAPIError, EC2UtilError """

        log = logging.getLogger(self.cls_logger + '.get_eni_id')

        # Get the instance-id
        if self.instance_id is None:
            msg = 'Instance ID not found for this machine'
            log.error(msg)
            raise OSError(msg)
        log.info('Found instance ID: {i}'.format(i=self.instance_id))

        log.debug('Querying EC2 instances...')
        try:
            response = self.client.describe_instances(
                    DryRun=False,
                    InstanceIds=[self.instance_id]
            )
        except ClientError:
            _, ex, trace = sys.exc_info()
            msg = 'Unable to query EC2 for instances\n{e}'.format(e=str(ex))
            log.error(msg)
            raise AWSAPIError, msg, trace
        log.debug('Found instance info: {r}'.format(r=response))

        # Find the ENI ID
        log.info('Looking for the ENI ID to alias...')
        eni_id = None
        try:
            for reservation in response['Reservations']:
                for instance in reservation['Instances']:
                    if instance['InstanceId'] == self.instance_id:
                        for network_interface in instance['NetworkInterfaces']:
                            if network_interface['Attachment']['DeviceIndex'] == interface:
                                eni_id = network_interface['NetworkInterfaceId']
        except KeyError:
            _, ex, trace = sys.exc_info()
            msg = 'ENI ID not found in AWS response for interface: {i}'.format(i=interface)
            log.error(msg)
            raise EC2UtilError, msg, trace

        log.info('Found ENI ID: {e}'.format(e=eni_id))
        return eni_id