__local_ip__ is an __undefined name__ in this context (could raise NameError at runtime) so this PR recommends the use of __self.local_ip__ instead.
flake8 testing of https://github.com/guardicore/monkey on Python 3.6.3
$ __flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics__
```
./infection_monkey/transport/ftp.py:86:29: F821 undefined name 'local_ip'
self.servsock.bind((local_ip,0))
^
```
Daniel Goldberg
cclauss
Itay Mizeretz