Adding recursion on child of List Field

Ensure no duplication of results with SearchFilter with Oracle databases.

Ability to customize DateTimeField with a custom datetime_parser

Made exception message more verbose

Handle AttributeError as well (when the imported module exists but the specified function/class does not).

Upgrade django-filter to 0.10.0

Remove unused import from docs example

Update extra_kwargs on model serializer for required and read_only

Ensures that the 'read_only' and 'required' keys from `extra_kwargs` are
retained when present. Closes #3091.

Update `get_serializer` signature (fix #2893)

- remove the `files` and `allow_add_remove` arguments that were part of the 2.x API.

Fixed #2900 -- Made example validator class in docs inherit from object

the specified function/class does not).

Fix ManyRelatedField.choices

Use choices from self.child_relation. 
We don't need to repeat ourself because can get out of sync.

Print helpful command if isort fails

Cleanup import following PEP 8 style guide

Use get_queryset() for RelatedField choices property

Progressing #2704