code: def translate_sites(self, indices=None, vector=None):
          
          if indices is None:
              indices = range(len(self))
          if vector is None:
              vector == [0, 0, 0]
          for i in indices:
              site = self._sites[i]
              new_site = Site(site.species, site.coords + vector,
                              properties=site.properties)
              self._sites[i] = new_site
docs: Translate specific sites by some vector, keeping the sites within the
          unit cell.
  
          Args:
              indices (list): List of site indices on which to perform the
                  translation.
              vector (3x1 array): Translation vector for sites.