def find(conditions)
      conditions = validate_conditions(conditions)

      @children.each do |child|        
        node = child.find(conditions)
        return node if node
      end
      nil
    end
def find(conditions)
      conditions = validate_conditions(conditions)

      @children.each do |child|        
        node = child.find(conditions)
        return node if node
      end
      nil
    end
Search the children of this node for the first node for which #find
 returns non +nil+. Returns the result of the #find call that succeeded.