def add(dcm)
      raise ArgumentError, "Invalid argument 'dcm'. Expected DObject, got #{dcm.class}." unless dcm.is_a?(DICOM::DObject)
      @dcm = dcm
      #load_patient_setup
      load_beams
    end
def add(dcm)
      raise ArgumentError, "Invalid argument 'dcm'. Expected DObject, got #{dcm.class}." unless dcm.is_a?(DICOM::DObject)
      @dcm = dcm
      #load_patient_setup
      load_beams
    end
Registers a DICOM Object to the Plan, and processes it
 to create (and reference) the beams contained in the object.

 @param [DICOM::DObject] dcm an RTPLAN DICOM object