class_docstr: Like CaselessLiteral, but returns the match as found
  instead of as defined.
code: def parseImpl(self, instring, loc, doActions=True):
      test = instring[loc : loc + self.matchLen]
      if test.upper() == self.match:
          return loc + self.matchLen, test
      # ~ raise ParseException( instring, loc, self.errmsg )
      exc = self.myException
      exc.loc = loc
      exc.pstr = instring
      raise exc
  
file_path: scikit-learn/doc/tutorial/machine_learning_map/parse_path.py
label_desc: Use image node_id 2 for calling the CaselessPreservingLiteral obj's underlying member method code with example usage: obj.parseImpl(instring, loc, doActions) and returns: unknown,  test