title: Trace: sys.argv[:] = args; TypeError: 'tuple' object does not support item assignment
body: <p>
  Try to trace pdb: </p>
  
  <p>python3 -m trace --trace pdb.py helloworld.py </p>
  
  <p>
      File "~/python362/lib/python3.6/pdb.py", line 1654, in main</p>
  
  <pre><code>sys.argv[:] = args
  </code></pre>
  
  <p>
  I expect sys.argv is a list, but python3 raises an error.</p>
  
  <p>
  TypeError: 'tuple' object does not support item assignment</p>