def _GetDenseDimensions(list_of_lists):
  """Returns the inferred dense dimensions of a list of lists."""
  if not isinstance(list_of_lists, (list, tuple)):
    return []
  elif not list_of_lists:
    return [0]
  else:
    return [len(list_of_lists)] + _GetDenseDimensions(list_of_lists[0])