code: def pad(iterable, padding=None, length=None):
      """Returns the sequence elements and then returns None up to the given size (or indefinitely if size is None)."""
      return islice(chain(iterable, repeat(padding)), length)
  
imports: from .widget_box import Box
  from .widget import register
  from .widget_core import CoreWidget
  from traitlets import Unicode, Dict, CInt, TraitError, validate, observe
  from .trait_types import TypedTuple
  from itertools import chain, repeat, islice
label_desc: Use image node_id 1 for calling a global function with example usage: pad(iterable, padding, length) and returns: islice