def element(tag)
      element = @elements[tag]
      unless element
        if tag.group_length?
          element = DictionaryElement.new(tag, 'Group Length', ['UL'], '1', '')
        else
          if tag.private?
            element = DictionaryElement.new(tag, 'Private', ['UN'], '1', '')
          else
            element = unknown_or_range_element(tag)
          end
        end
      end
      element
    end
def element(tag)
      element = @elements[tag]
      unless element
        if tag.group_length?
          element = DictionaryElement.new(tag, 'Group Length', ['UL'], '1', '')
        else
          if tag.private?
            element = DictionaryElement.new(tag, 'Private', ['UN'], '1', '')
          else
            element = unknown_or_range_element(tag)
          end
        end
      end
      element
    end
Identifies the DictionaryElement that corresponds to the given tag.

 @note If a given tag doesn't return a dictionary match, a new DictionaryElement is created.
   * For private tags, a name 'Private' and VR 'UN' is assigned
   * For unknown tags, a name 'Unknown' and VR 'UN' is assigned
 @param [String] tag the tag of the element
 @return [DictionaryElement] a corresponding DictionaryElement