new_contents: from parcels import Particle, ParticleSet, JITParticle, JITParticleSet
  from parcels import NEMOGrid, ParticleFile, AdvectionRK4
  from argparse import ArgumentParser
  
  
  pclasses = {'scipy': (Particle, ParticleSet),
              'jit': (JITParticle, JITParticleSet)}
  
  
  def moving_eddies(grid, npart, mode='jit', verbose=False):
      """Configuration of a particle set that follows two moving eddies
  
      :arg grid: :class NEMOGrid: that defines the flow field
      :arg npart: Number of particles to intialise"""
  
      # Determine particle and set classes according to mode
      ParticleClass, ParticleSetClass = pclasses[mode]
  
      lon = [3.3, 3.3]
      lat = [46., 47.8]
      pset = ParticleSetClass(2, grid, lon=lon, lat=lat)
  
      if verbose:
          print("Initial particle positions:")
          for p in pset:
              print(p)
  
      out = ParticleFile(name="EddyParticle", particleset=pset)
      out.write(pset, 0.)
      current = 0.
      for _ in range(24 * 25):
          pset.execute(AdvectionRK4, time=current,
                       timesteps=12, dt=300.)
          out.write(pset, current)
          current += 3600.
  
      if verbose:
          print("Final particle positions:")
          for p in pset:
              print(p)
  
  if __name__ == "__main__":
      p = ArgumentParser(description="""
  Example of particle advection around an idealised peninsula""")
      p.add_argument('mode', choices=('scipy', 'jit'), nargs='?', default='jit',
                     help='Execution mode for performing RK4 computation')
      p.add_argument('-p', '--particles', type=int, default=20,
                     help='Number of particles to advect')
      p.add_argument('-v', '--verbose', action='store_true', default=False,
                     help='Print particle information before and after execution')
      p.add_argument('--profiling', action='store_true', default=False,
                     help='Print profiling information after run')
      args = p.parse_args()
  
      # Open grid file set
      grid = NEMOGrid.from_file('moving_eddies')
  
      if args.profiling:
          from cProfile import runctx
          from pstats import Stats
          runctx("moving_eddies(grid, args.particles, mode=args.mode, \
                                verbose=args.verbose)",
                 globals(), locals(), "Profile.prof")
          Stats("Profile.prof").strip_dirs().sort_stats("time").print_stats(10)
      else:
          moving_eddies(grid, args.particles, mode=args.mode, verbose=args.verbose)
  
subject: Add simple test setup that follows two particles