code: def postfix(self):
      localctx = LaTeXParser.PostfixContext(self, self._ctx, self.state)
      self.enterRule(localctx, 18, self.RULE_postfix)
      try:
          self.enterOuterAlt(localctx, 1)
          self.state = 154
          self.exp(0)
          self.state = 158
          self._errHandler.sync(self)
          _alt = self._interp.adaptivePredict(self._input, 8, self._ctx)
          while _alt != 2 and _alt != ATN.INVALID_ALT_NUMBER:
              if _alt == 1:
                  self.state = 155
                  self.postfix_op()
              self.state = 160
              self._errHandler.sync(self)
              _alt = self._interp.adaptivePredict(
                  self._input, 8, self._ctx
              )
  
      except RecognitionException as re:
          localctx.exception = re
          self._errHandler.reportError(self, re)
          self._errHandler.recover(self, re)
      finally:
          self.exitRule()
      return localctx
  
imports: from antlr4 import *
  from io import StringIO
  import sys
label_desc: Use image node_id 11 for calling the LaTeXParser obj's underlying member method code with example usage: obj.postfix() and returns: localctx