message: Update Line 246
diff: @@ -243,8 +243,11 @@ def is_nested(seq):
  def flatten(structure, expand_composites=False):
  """Returns a flat list from a given nested structure.
  - If nest is not a sequence, tuple (or a namedtuple), dict, or an attrs class,
  - then returns a single-element list:
  + If nest is not a structure (which can be a scalar, or
  + tuple or dict or list of constructed scalars and/or other tuples/lists,
  + or a scalar object. Note, numpy arrays are considered scalars.), tuple
  + (or a namedtuple), dict, or an attrs class, then returns a single-element
  + list:
  [nest].
  In the case of dict instances, the sequence consists of the values, sorted by
  