Marshmallow

*******************

Bug fixes:

- Prevent ``TypeError`` when a non-collection is passed to a ``Schema`` with ``many=True``.
Instead, raise ``ValidationError`` with ``{'_schema': ['Invalid input type.']}`` (:issue:`906`).
- Fix ``root`` attribute for nested container fields on list
on inheriting schemas (:issue:`956`). Thanks :user:`bmcbu`
for reporting.

These fixes were backported from 3.0.0b15 and 3.0.0b16.

*******************

Bug fixes:

- Handle empty SQLAlchemy lazy lists gracefully when dumping (:issue:`948`).
Thanks :user:`vke-code` for the catch and :user:`YuriHeupa` for the patch.

*******************

Bug fixes:

- Respect ``load_from`` when reporting errors for ``validates('field_name')``
(:issue:`748`). Thanks :user:`m-novikov` for the catch and patch.

*******************

Bug fixes:

- Fix passing ``only`` as a string to ``nested`` when the passed field
defines ``dump_to`` (:issue:`800`, :issue:`822`). Thanks
:user:`deckar01` for the catch and patch.

*******************

Bug fixes:

- Fix a race condition in validation when concurrent threads use the
same ``Schema`` instance (:issue:`783`). Thanks :user:`yupeng0921` and
:user:`lafrech` for the fix.
- Fix serialization behavior of
``fields.List(fields.Integer(as_string=True))`` (:issue:`788`). Thanks
:user:`cactus` for reporting and :user:`lafrech` for the fix.
- Fix behavior of ``exclude`` parameter when passed from parent to
nested schemas (:issue:`728`). Thanks :user:`timc13` for reporting and
:user:`deckar01` for the fix.

*******************

Bug fixes:

- :cve:`CVE-2018-17175`: Fix behavior when an empty list is passed as the ``only`` argument
(:issue:`772`). Thanks :user:`deckar01` for reporting and thanks
:user:`lafrech` for the fix.