code: def _syscal_write_quadpoles(fid, quadpoles):
      
      fid.write('# A B M N\n')
      for nr, quadpole in enumerate(quadpoles):
          fid.write(
              '{0} {1} {2} {3} {4}\n'.format(
                  nr, quadpole[0], quadpole[1], quadpole[2], quadpole[3]))
docs: helper function that writes the actual measurement configurations to a
      file descriptor.
  
      Parameters
      ----------
      fid: file descriptor
          data is written here
      quadpoles: numpy.ndarray
          measurement configurations