**Description of the false positive** <!-- Please explain briefly why you think it shouldn't be included. --> Once ipdb is initialized and if i do CTRL-C, the code is reachable. **URL to the alert on the project page on LGTM.com** https://lgtm.com/projects/g/Azure/sonic-buildimage/snapshot/05ece9b3196563683caf191febe1a4d23c22d3e0/files/dockers/docker-sflow/port_index_mapper.py?sort=name&dir=ASC&mode=heatmap#x461799ad8bd2f5ca:1 <!-- 1. Open the project on LGTM.com. For example, https://lgtm.com/projects/g/pallets/click/. 2. Switch to the `Alerts` tab. For example, https://lgtm.com/projects/g/pallets/click/alerts/. 3. Scroll to the alert that you would like to report. 4. Click on the right most icon `View this alert within the complete file`. 5. A new browser tab opens. Copy and paste the page URL here. For example, https://lgtm.com/projects/g/pallets/click/snapshot/719fb7d8322b0767cdd1e5903ba3eb3233ba8dd5/files/click/_winconsole.py#xa08d213ab3289f87:1. -->