def transformString( self, instring ):
        out = []
        lastE = 0
        # force preservation of <TAB>s, to minimize unwanted transformation of string, and to
        # keep string locs straight between transformString and scanString
        self.keepTabs = True
        try:
            for t,s,e in self.scanString( instring ):
                out.append( instring[lastE:s] )
                if t:
                    if isinstance(t,ParseResults):
                        out += t.asList()
                    elif isinstance(t,list):
                        out += t
                    else:
                        out.append(t)
                lastE = e
            out.append(instring[lastE:])
            out = [o for o in out if o]
            return "".join(map(_ustr,_flatten(out)))
        except ParseBaseException as exc:
            if ParserElement.verbose_stacktrace:
                raise
            else:
                # catch and re-raise exception from here, clears out pyparsing internal stack trace
                raise exc
Extension to C{L{scanString}}, to modify matching text with modified tokens that may
dataset/ETHPy150Open pypa/pip/pip/_vendor/pyparsing.py/ParserElement.transformString