DjangoFilterBackend' object has no attribute 'get_schema_operation_parameters'

[AlexIvanchyk]

Checklist

• I have verified that that issue exists against the master branch of Django REST framework.
• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• This is not a usage question. (Those should be directed to the discussion group instead.)
• This cannot be dealt with as a third party library. (We prefer new functionality to be in the form of third party libraries where possible.)
• I have reduced the issue to the simplest possible case.
• I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

1. DRF version 3.10.0.
2. Create simple view with DjangoFilterBackend from django_filters.rest_framework

from rest_framework import generics
from django_filters import rest_framework as filters

class SimpleView(generics.ListAPIView):
    serializer_class = SomeSerializer
    filter_backends = (filters.DjangoFilterBackend,)

3. Run server and try generate OpenAPI schema(by view)

Expected behavior

Should work

Actual behavior

This causes a corresponding error:

Internal Server Error: /openapi
Traceback (most recent call last):
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner
    response = get_response(request)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/django/core/handlers/base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/django/core/handlers/base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/django/views/generic/base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/views.py", line 497, in dispatch
    response = self.handle_exception(exc)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/schemas/views.py", line 48, in handle_exception
    return super().handle_exception(exc)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/views.py", line 457, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/views.py", line 468, in raise_uncaught_exception
    raise exc
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/views.py", line 494, in dispatch
    response = handler(request, *args, **kwargs)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/schemas/views.py", line 37, in get
    schema = self.schema_generator.get_schema(request, self.public)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/schemas/openapi.py", line 62, in get_schema
    paths = self.get_paths(None if public else request)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/schemas/openapi.py", line 49, in get_paths
    operation = view.schema.get_operation(path, method)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/schemas/openapi.py", line 96, in get_operation
    parameters += self._get_filter_parameters(path, method)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/rest_framework/schemas/openapi.py", line 185, in _get_filter_parameters
    parameters += filter_backend().get_schema_operation_parameters(self.view)
  File "/Users/alex/PycharmProjects/handiscover_api/venv/lib/python3.7/site-packages/django_filters/utils.py", line 61, in __getattr__
    return self.__getattribute__(name)
AttributeError: 'DjangoFilterBackend' object has no attribute 'get_schema_operation_parameters'

[carltongibson]

Please see carltongibson/django-filter#1086

pip install -U django-filter

(pip list --outdated is your friend here.)