code: def _rr_bounds(rr, chunk=200):
      # chunk data nicely
      bounds = np.concatenate([np.arange(0, len(rr), chunk), [len(rr)]])
      return zip(bounds[:-1], bounds[1:])
  
imports: from copy import deepcopy
  import numpy
  from .._fiff.constants import FIFF
  from ..bem import _import_openmeeg, _make_openmeeg_geometry
  from ..fixes import bincount, jit
  from ..parallel import parallel_func
  from ..surface import _jit_cross, _project_onto_surface
  from ..transforms import apply_trans, invert_transform
  from ..utils import _check_option, _pl, fill_doc, logger, verbose, warn
label_desc: Use image node_id 12 for calling a global function with example usage: _rr_bounds(rr, chunk) and returns: zip