code: def find_equivalent_sites(self, site):
          
          for sites in self.equivalent_sites:
              if site in sites:
                  return sites
  
          raise ValueError("Site not in structure")
docs: Finds all symmetrically equivalent sites for a particular site
  
          Args:
              site (PeriodicSite): A site in the structure
  
          Returns:
              ([PeriodicSite]): List of all symmetrically equivalent sites.