code: function Snippet(file) {
    if (!(this instanceof Snippet)) {
      return new Snippet(file);
    }
    if (typeof file === 'string') {
      file = {path: file};
    }
  
    this.history = [];
  
    if (typeof file === 'object') {
      this.visit('set', file);
    }
  
    this.cwd = this.cwd || process.cwd();
    this.content = this.content || null;
    this.options = this.options || {};
  }
docs: Create a new `Snippet`, optionally passing a `file` object
  to start with.
  
  @param {Object} `file`
  @api public