title: signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object
body: <p>I am trying to write some code to perform some packet sniffing with python
  using pyshark.I have the following piece of code:</p>
  
  <pre><code>import pyshark
  print('Pyshark demo')
  capture = pyshark.LiveCapture(interface='enp0s8')
  </code></pre>
  
  <p>However when I try to run this script I get the following stack trace:</p>
  
  <pre><code>Pyshark demo
  Exception ignored in: &lt;bound method BaseEventLoop.__del__ of &lt;_UnixSelectorEventLoop running=False closed=True debug=False&gt;&gt;
  Traceback (most recent call last):
    File "/usr/lib/python3.5/asyncio/base_events.py", line 431, in __del__
    File "/usr/lib/python3.5/asyncio/unix_events.py", line 58, in close
    File "/usr/lib/python3.5/asyncio/unix_events.py", line 139, in remove_signal_handler
    File "/usr/lib/python3.5/signal.py", line 47, in signal
  TypeError: signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object
  </code></pre>
  
  <p>I have install pyshark.Do you have any idea what is causing this problem?</p>
  
  <p>I run this on an ubuntu server 16.04</p>