def value(tag)
      raise ArgumentError, "Expected String, got #{tag.class}." unless tag.is_a?(String)
      raise ArgumentError, "Expected a valid tag of format 'GGGG,EEEE', got #{tag}." unless tag.tag?
      pos = @tags.index(tag)
      if pos
        return @values[pos]
      else
        logger.warn("The specified tag (#{tag}) was not found in the list of tags to be anonymized.")
        return nil
      end
    end
def value(tag)
      raise ArgumentError, "Expected String, got #{tag.class}." unless tag.is_a?(String)
      raise ArgumentError, "Expected a valid tag of format 'GGGG,EEEE', got #{tag}." unless tag.tag?
      pos = @tags.index(tag)
      if pos
        return @values[pos]
      else
        logger.warn("The specified tag (#{tag}) was not found in the list of tags to be anonymized.")
        return nil
      end
    end
Gives the value which will be used when anonymizing this tag.

 @note If enumeration is selected for a string type tag, a number will be
   appended in addition to the string that is returned here.

 @param [String] tag a data element tag
 @return [String, Integer, Float, NilClass] the replacement value for the specified tag, or nil if the tag is not matched