def create_frame(uid, indicator=nil)
      raise ArgumentError, "Invalid argument 'uid'. Expected String, got #{uid.class}." unless uid.is_a?(String)
      raise ArgumentError, "Invalid argument 'indicator'. Expected String or nil, got #{indicator.class}." unless [String, NilClass].include?(indicator.class)
      frame = Frame.new(uid, self, :indicator => indicator)
      add_frame(frame)
      @dataset.add_frame(frame)
      return frame
    end
def create_frame(uid, indicator=nil)
      raise ArgumentError, "Invalid argument 'uid'. Expected String, got #{uid.class}." unless uid.is_a?(String)
      raise ArgumentError, "Invalid argument 'indicator'. Expected String or nil, got #{indicator.class}." unless [String, NilClass].include?(indicator.class)
      frame = Frame.new(uid, self, :indicator => indicator)
      add_frame(frame)
      @dataset.add_frame(frame)
      return frame
    end
Creates (and returns) a Frame instance added to this Patient.

 === Parameters

 * <tt>uid</tt> -- The Frame of Reference UID string.
 * <tt>indicator</tt> -- The Position Reference Indicator string. Defaults to nil.

 @param [String] uid the Frame of Reference UID string (0020,0052)
 @param [String, NilClass] indicator the Position Reference Indicator (0020,1040)
 @return [Frame] the created frame