def get_return_type_indexes(self, data):
        """Get from a docstring the return parameter type indexes.
        In javadoc style it is after @rtype.

        :param data: string to parse
        :returns: start and end indexes of found element else (-1, -1)
          Note: the end index is the index after the last included character or -1 if
          reached the end
        :rtype: tuple

        """
        start, end = -1, -1
        stl_rtype = self.opt['rtype'][self.style['in']]['name']
        if self.style['in'] in self.tagstyles + ['unknown']:
            dstart, dend = self.get_return_description_indexes(data)
            # search the start
            if dstart >= 0 and dend > 0:
                idx = self.get_elem_index(data[dend:])
                if idx >= 0 and data[dend + idx:].startswith(stl_rtype):
                    idx = dend + idx + len(stl_rtype)
                    m = re.match(r'\W*(\w+)', data[idx:])
                    if m:
                        first = m.group(1)
                        start = data[idx:].find(first) + idx
            # search the end
            idx = self.get_elem_index(data[start:])
            if idx > 0:
                end = idx + start

        if self.style['in'] in ['params', 'unknown'] and (start, end) == (-1, -1):
            # TODO: manage this
            pass

        return start, end
Get from a docstring the return parameter type indexes.
        In javadoc style it is after @rtype.

        :param data: string to parse
        :returns: start and end indexes of found element else (-1, -1)
          Note: the end index is the index after the last included character or -1 if
          reached the end
        :rtype: tuple