def as_name(value)
      case true
      when value.tag?
        element(value).name
      when value.dicom_name?
        @methods_from_names.has_key?(value) ? value.to_s : nil
      when value.dicom_method?
        @names_from_methods[value.to_sym]
      else
        nil
      end
    end
def as_name(value)
      case true
      when value.tag?
        element(value).name
      when value.dicom_name?
        @methods_from_names.has_key?(value) ? value.to_s : nil
      when value.dicom_method?
        @names_from_methods[value.to_sym]
      else
        nil
      end
    end
Gives the name corresponding to the specified element string value.

 @param [String] value an element tag, element name or an element's method name
 @return [String, NilClass] the matched element name, or nil if no match is made