docs: function _addToTree(tree, branchToken, leafToken) {
    /* eslint-disable max-len, no-param-reassign */
    const leafValue = Utils.merge(tree[branchToken].fields[leafToken] || {}, _parseLeafToken(leafToken));
    tree[branchToken].fields[leafToken] = leafValue;
    /* eslint-enable max-len, no-param-reassign */
  
    return tree;
  }