code: def _write_rigid_information(xml_file, rigid_bodies):
      
  
      if not all(body is None for body in rigid_bodies):
          xml_file.write('<body>\n')
          for body in rigid_bodies:
              if body is None:
                  body = -1
              xml_file.write('{}\n'.format(int(body)))
          xml_file.write('</body>\n')
docs: Write rigid body information.
  
      Parameters
      ----------
      xml_file : file object
          The file object of the hoomdxml file being written
      rigid_bodies : list, len=n_particles
          The rigid body that each particle belongs to (-1 for none)