code: def setDriftLength(self, x):
          
          if x != self.getDriftLength():
              self._setDriftList(x)
              self.refresh = True
docs: set lengths for drift sections
  
          :param x: single double or list
          :return: None
  
          :Example:
  
          >>> import beamline
          >>> chi = beamline.mathutils.Chicane(bend_length=1,bend_field=0.5,drift_length=1,gamma=1000)
          >>> chi.getMatrix()
          >>> r56 = chi.getR(5,6)  # r56 = -0.432
          >>> chi.setDriftLength([2,4,2])
          >>> # same effect (to R56) as ``chi.setDriftLength([2,4])`` or ``chi.setDriftLength([2])``
          >>> # or ``chi.setDriftLength(2)``
          >>> r56 = chi.getR(5,6)  # r56 = -0.620