LGTM.com - false positive: 0 != None

**Platform: Python**

**Description of the false positive**

Apparently
```python
if n == 0:
print("a")
elif not n:
print("b")
else:
print("c")
```

Shows the elif as dead code. However if n is `None` it will get triggered.

**URL to the alert on the project page on LGTM.com**: https://lgtm.com/projects/g/secdev/scapy/snapshot/4d06eb2812a98a1001478bf06e033fbbb2afbef7/files/scapy/volatile.py?sort=name&dir=ASC&mode=heatmap#xf144c20a181fcce0:1