Generate an HTML table of merge statistics.

    Args:
      feed_merger: The FeedMerger instance.

    Returns:
      The generated HTML as a string.

def _GenerateStatsTable(self, feed_merger):
    """Generate an HTML table of merge statistics.

    Args:
      feed_merger: The FeedMerger instance.

    Returns:
      The generated HTML as a string.
    """
    rows = []
    rows.append('<tr><th class="header"/><th class="header">Merged</th>'
                '<th class="header">Copied from old feed</th>'
                '<th class="header">Copied from new feed</th></tr>')
    for merger in feed_merger.GetMergerList():
      stats = merger.GetMergeStats()
      if stats is None:
        continue
      merged, not_merged_a, not_merged_b = stats
      rows.append('<tr><th class="header">%s</th>'
                  '<td class="header">%d</td>'
                  '<td class="header">%d</td>'
                  '<td class="header">%d</td></tr>' %
                  (merger.DATASET_NAME, merged, not_merged_a, not_merged_b))
    return '<table>%s</table>' % '\n'.join(rows)