def tags(name = nil)
      list = stable_sort_by(@tags + convert_ref_tags, &:tag_name)
      return list unless name
      list.select {|tag| tag.tag_name.to_s == name.to_s }
    end
def tags(name = nil)
      list = stable_sort_by(@tags + convert_ref_tags, &:tag_name)
      return list unless name
      list.select {|tag| tag.tag_name.to_s == name.to_s }
    end
Returns a list of tags specified by +name+ or all tags if +name+ is not specified.

 @param [#to_s] name the tag name to return data for, or nil for all tags
 @return [Array<Tags::Tag>] the list of tags by the specified tag name