code: def comp_nofunc(self):
      localctx = LaTeXParser.Comp_nofuncContext(
          self, self._ctx, self.state
      )
      self.enterRule(localctx, 36, self.RULE_comp_nofunc)
      try:
          self.state = 249
          self._errHandler.sync(self)
          la_ = self._interp.adaptivePredict(self._input, 21, self._ctx)
          if la_ == 1:
              self.enterOuterAlt(localctx, 1)
              self.state = 244
              self.group()
              pass
  
          elif la_ == 2:
              self.enterOuterAlt(localctx, 2)
              self.state = 245
              self.abs_group()
              pass
  
          elif la_ == 3:
              self.enterOuterAlt(localctx, 3)
              self.state = 246
              self.atom()
              pass
  
          elif la_ == 4:
              self.enterOuterAlt(localctx, 4)
              self.state = 247
              self.floor()
              pass
  
          elif la_ == 5:
              self.enterOuterAlt(localctx, 5)
              self.state = 248
              self.ceil()
              pass
  
      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 20 for calling the LaTeXParser obj's underlying member method code with example usage: obj.comp_nofunc() and returns: localctx