def get_tag(name)
      tag = nil
      name = name.to_s.downcase
      @tag_name_pairs_cache ||= Hash.new
      return @tag_name_pairs_cache[name] unless @tag_name_pairs_cache[name].nil?
      @elements.each_value do |element|
        next unless element.name.downcase == name
        tag = element.tag
        break
      end
      @tag_name_pairs_cache[name]=tag
      return tag
    end
def get_tag(name)
      tag = nil
      name = name.to_s.downcase
      @tag_name_pairs_cache ||= Hash.new
      return @tag_name_pairs_cache[name] unless @tag_name_pairs_cache[name].nil?
      @elements.each_value do |element|
        next unless element.name.downcase == name
        tag = element.tag
        break
      end
      @tag_name_pairs_cache[name]=tag
      return tag
    end
Gives the tag that matches the supplied data element name, by searching the element dictionary.

 @param [String] name a data element name
 @return [String, NilClass] the corresponding element tag, or nil if no match is made