code: def find_primitive(self):
          
          lattice, scaled_positions, numbers = spglib.find_primitive(
              self._cell, symprec=self._symprec)
  
          species = [self._unique_species[i - 1] for i in numbers]
  
          return Structure(lattice, species, scaled_positions,
                           to_unit_cell=True).get_reduced_structure()
docs: Find a primitive version of the unit cell.
  
          Returns:
              A primitive cell in the input cell is searched and returned
              as an Structure object. If no primitive cell is found, None is
              returned.