the to_dict() method generates a {class_name: value} dictionary,
for both the nested and non-nested case. However, before this patch,
the from_dict() method expects a plain list of child IE dicts
in the nested case. This is illogical.
Let's make sure from_dict always expectes a {class_name: value} dict
for both nested and non-nested situations.
Change-Id: I07e4feb3800b420d8be7aae8911f828f1da9dab8
a9b21bdb1f