Hello,
if I start mitmproxy or mitmweb, a module is missing:

mitmproxy
Traceback (most recent call last):
File "/usr/local/bin/mitmproxy", line 7, in <module>
from libmproxy.main import mitmproxy
File "/usr/local/lib/python2.7/dist-packages/libmproxy/main.py", line 6, in <module>
import netlib.version_check
File "/usr/local/lib/python2.7/dist-packages/netlib/version_check.py", line 6, in <module>
import OpenSSL
File "/usr/local/lib/python2.7/dist-packages/OpenSSL/init.py", line 8, in <module>
from OpenSSL import crypto, SSL
File "/usr/local/lib/python2.7/dist-packages/OpenSSL/crypto.py", line 12, in <module>
from cryptography import x509
File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/init.py", line 8, in <module>
from cryptography.x509.base import (
File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/base.py", line 16, in <module>
from cryptography.x509.extensions import Extension, ExtensionType
File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/extensions.py", line 13, in <module>
from asn1crypto.keys import PublicKeyInfo
ImportError: No module named asn1crypto.keys