code: function bulksDoc (docs, qs0, callback0) {
        const { opts, callback } = getCallback(qs0, callback0)
        return relax({
          db: dbName,
          path: '_bulk_docs',
          body: docs,
          method: 'POST',
          qs: opts
        }, callback)
      }
docs: http://docs.couchdb.org/en/latest/api/database/bulk-api.html#post--db-_bulksDoc