code: function ( level, depth ) {
              if ( level >= depth ) {
                  return this;
              }
              if ( this.childrenCount() === 0 ) {
                  return;
              }
  
              for ( var i = 0, n = this.childrenCount(); i < n; i++ ) {
                  var leftmostDescendant = this.childAt( i ).leftMost( level + 1, depth );
                  if ( leftmostDescendant ) {
                      return leftmostDescendant;
                  }
              }
          }
docs: Returns the leftmost child at specific level, (initial level = 0)
  @param level
  @param depth
  @returns {*}