code: def dim(self):
          
          if len(self._orb.vxvv) == 2:
              return 1
          elif len(self._orb.vxvv) == 3 or len(self._orb.vxvv) == 4:
              return 2
          elif len(self._orb.vxvv) == 5 or len(self._orb.vxvv) == 6:
              return 3
docs: NAME:
  
             dim
  
          PURPOSE:
  
             return the dimension of the Orbit
  
          INPUT:
  
             (none)
  
          OUTPUT:
  
             dimension
  
          HISTORY:
  
             2011-02-03 - Written - Bovy (NYU)