def get_next_section_start_line(self, data):
        """Get the starting line number of next section.
        It will return -1 if no section was found.
        The section is a section key (e.g. 'Parameters') followed by underline
        (made by -), then the content

        :param data: a list of strings containing the docstring's lines
        :type data: list(str)
        :returns: the index of next section else -1

        """
        start = -1
        for i, line in enumerate(data):
            if start != -1:
                # we found the key so check if this is the underline
                if line.strip() and isin_alone(['-' * len(line.strip())], line):
                    break
                else:
                    start = -1
            if isin_alone(self.opt.values(), line):
                start = i
        return start
Get the starting line number of next section.
        It will return -1 if no section was found.
        The section is a section key (e.g. 'Parameters') followed by underline
        (made by -), then the content

        :param data: a list of strings containing the docstring's lines
        :type data: list(str)
        :returns: the index of next section else -1