Dear Authors,
  It would be convenient to improve the method

kwant.lattice.Monatomic.n_closest

to include an argument "range"
or even two arguments: range_min = 0 and range_max
so that it returns the sites within a range from the given point.
  This is useful to e.g. specify the hoppings between incommensurate lattices.

Thanks,
Sergey