Write shared location information to the SHARED file in .dist-info.
        :param paths: A dictionary as described in the documentation for
        :meth:`shared_locations`.
        :param dry_run: If True, the action is logged but no file is actually
                        written.
        :return: The path of the file written to.

def write_shared_locations(self, paths, dry_run=False):
        """
        Write shared location information to the SHARED file in .dist-info.
        :param paths: A dictionary as described in the documentation for
        :meth:`shared_locations`.
        :param dry_run: If True, the action is logged but no file is actually
                        written.
        :return: The path of the file written to.
        """
        shared_path = os.path.join(self.path, 'SHARED')
        logger.info('creating %s', shared_path)
        if dry_run:
            return None
        lines = []
        for key in ('prefix', 'lib', 'headers', 'scripts', 'data'):
            path = paths[key]
            if os.path.isdir(paths[key]):
                lines.append('%s=%s' % (key,  path))
        for ns in paths.get('namespace', ()):
            lines.append('namespace=%s' % ns)

        with codecs.open(shared_path, 'w', encoding='utf-8') as f:
            f.write('\n'.join(lines))
        return shared_path