def _interpolate_some(self, option, accum, rest, section, map, depth):
        if depth > MAX_INTERPOLATION_DEPTH:
            raise InterpolationDepthError(option, section, rest)
        while rest:
            p = rest.find("%")
            if p < 0:
                accum.append(rest)
                return
            if p > 0:
                accum.append(rest[:p])
                rest = rest[p:]
            # p is no longer used
            c = rest[1:2]
            if c == "%":
                accum.append("%")
                rest = rest[2:]
            elif c == "(":
                m = self._interpvar_re.match(rest)
                if m is None:
                    raise InterpolationSyntaxError(option, section,
                        "bad interpolation variable reference %r" % rest)
                var = self.optionxform(m.group(1))
                rest = rest[m.end():]
                try:
                    v = map[var]
                except __HOLE__:
                    raise InterpolationMissingOptionError(
                        option, section, rest, var)
                if "%" in v:
                    self._interpolate_some(option, accum, v,
                                           section, map, depth + 1)
                else:
                    accum.append(v)
            else:
                raise InterpolationSyntaxError(
                    option, section,
                    "'%%' must be followed by '%%' or '(', found: %r" % (rest,))
dataset/ETHPy150Open deanhiller/databus/webapp/play1.3.x/python/Lib/ConfigParser.py/SafeConfigParser._interpolate_some