code: def _neighbors(coordinate, radius):
      
      ranges = (xrange(n-radius, n+radius+1) for n in coordinate.tolist())
      return numpy.array(list(itertools.product(*ranges)))
docs: Returns coordinates around given coordinate, within given radius.
      Includes given coordinate.
  
      @param coordinate (numpy.array) N-dimensional integer coordinate
      @param radius (int) Radius around `coordinate`
  
      @return (numpy.array) List of coordinates