- version update to 2.19.1
- Fix bug where ``Nested(many=True)`` would skip first element when
serializing a generator (:issue:`1163`). Thanks :user:`khvn26` for the
catch and patch.
- A `RemovedInMarshmallow3` warning is raised when using
`fields.FormattedString`. Use `fields.Method` or `fields.Function`
instead (:issue:`1141`).
- A ``ChangedInMarshmallow3Warning`` is no longer raised when
``strict=False`` (:issue:`1108`). Thanks :user:`Aegdesil` for
reporting.
- Add warnings for functions in ``marshmallow.utils`` that are removed in
marshmallow 3.
- Copying ``missing`` with ``copy.copy`` or ``copy.deepcopy`` will not
duplicate it (:pr:`1099`).
- Add ``marshmallow.__version_info__`` (:pr:`1074`).
- Add warnings for API that is deprecated or changed to help users
prepare for marshmallow 3 (:pr:`1075`).
- Prevent memory leak when dynamically creating classes with ``type()``
(:issue:`732`). Thanks :user:`asmodehn` for writing the tests to
reproduce this issue.
- Prevent warning about importing from ``collections`` on Python 3.7
(:issue:`1027`). Thanks :user:`nkonin` for reporting and
:user:`jmargeta` for the PR.
- Remove spurious warning about implicit collection handling
(:issue:`998`). Thanks :user:`lalvarezguillen` for reporting.
- Allow username without password in basic auth part of the url in
``fields.Url`` (:pr:`982`). Thanks user:`alefnula` for the PR.
- 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