title: Antlr4 ParserATNSimulator Debugger generate no Output
body: <p>Is there a possibility to get the ParserATNSimulator Debuggingmessaging in python3 to work?</p>
  <p>I tried to get to the core of ANTLR4 for python 3 and messed a bit with the ATN Simulation. There i wonder about the Class Attributes in ParserATNSimulator() for debugging.</p>
  <pre><code>class ParserATNSimulator(ATNSimulator):
  
      debug = False
      debug_list_atn_decisions = False
      dfa_debug = False
      retry_debug = False
  </code></pre>
  <p>Checking the code i see that this should print a lot of Information about the decision making in ANTLR4.</p>
  <pre><code>if self.debug or self.debug_list_atn_decisions:
  print(&quot;predictATN decision &quot; + str(dfa.decision) +
        &quot; exec LA(1)==&quot; + self.getLookaheadName(input) +
        &quot;, outerContext=&quot; + outerContext.toString(self.parser))
  </code></pre>
  <p>Unfortunately it Producing no output when i tried to set it True. Other
  parts work as expected.
  Is there a possibility to get this information?</p>
  <pre><code>  def main(argv):
      istream = FileStream(argv[1])
      lexer = ExLexer(istream)
      stream = CommonTokenStream(lexer)
      parser = ExParser(stream)
      parser._interp.debug = True
      parser._interp.debug_list_atn_decisions = True
      parser._interp.dfa_debug = True
      parser._interp.retry_debug = True
      parser.stat()
  </code></pre>
  <p>Thanks in advance!</p>