code: def delta_E( self ):
          
          site_delta_E = self.final_site.energy - self.initial_site.energy
          if self.nearest_neighbour_energy:
              site_delta_E += self.nearest_neighbour_delta_E()
          if self.coordination_number_energy:
              site_delta_E += self.coordination_number_delta_E()
          return site_delta_E
docs: The change in system energy if this jump were accepted.
  
          Args:
              None
  
          Returns:
              (Float): delta E