code: def get_equilibrium_reaction_energy(self, entry):
          
          if entry not in self.stable_entries:
              raise ValueError("Equilibrium reaction energy is available only "
                               "for stable entries.")
          if entry.is_element:
              return 0
          entries = [e for e in self.stable_entries if e != entry]
          modpd = PhaseDiagram(entries, self.elements)
          return modpd.get_decomp_and_e_above_hull(entry,
                                                   allow_negative=True)[1]
docs: Provides the reaction energy of a stable entry from the neighboring
          equilibrium stable entries (also known as the inverse distance to
          hull).
  
          Args:
              entry: A PDEntry like object
  
          Returns:
              Equilibrium reaction energy of entry. Stable entries should have
              equilibrium reaction energy <= 0.