code: function parseCalendar($calendar) {
    const data = [];
    $calendar.find('rect').each((i, elm) => {
      const $rect = cheerio(elm);
      const date = $rect.attr('data-date');
      if (!date) {
        return;
      }
      data.push({
        date,
        count: parseInt($rect.attr('data-count'), 10)
      });
    });
    return data;
  }
docs: Parse HTML to list of contribution
  
  @param {Object} $calendar - cheerio object
  @return {Array<{date: string, count: number}>}