Fixed #23860 -- Documented import order convention.

* Use ``InitialCaps`` for class names (or for factory functions that

  return classes).

* Use convenience imports whenever available. For example, do this::

      from django.views.generic import View

  Don't do this::

      from django.views.generic.base import View

* In docstrings, follow :pep:`257`. For example::

      def foo():

          """

          ...

Imports

-------

* Use `isort <https://github.com/timothycrosley/isort#readme>`_ to automate

  import sorting using the guidelines below.

  Quick start:

  .. code-block:: bash

      $ pip install isort

      $ isort -rc .

  This runs ``isort`` recursively from your current directory, modifying any

  files that don't conform to the guidelines. If you need to have imports out

  of order (to avoid a circular import, for example) use a comment like this::

      import module  # isort:skip

* Put imports in these groups: future, standard library, third-party libraries,

  other Django components, local Django component, try/excepts. Sort lines in

  each group alphabetically by the full module name. Place all ``import module``

  statements before ``from module import objects`` in each section.

* On each line, alphabetize the items with the upper case items grouped before

  the lower case items.

* Break long lines using parentheses and indent continuation lines by 4 spaces.

  Include a trailing comma after the last import and put the closing

  parenthesis on its own line.

  Use a single blank line between the last import and any module level code,

  and use two blank lines above the first function or class.

  For example (comments are for explanatory purposes only):

  .. snippet::

      :filename: django/contrib/admin/example.py

      # future

      from __future__ import unicode_literals

      # standard library

      import json

      from itertools import chain

      # third-party

      import bcrypt

      # Django

      from django.http import Http404

      from django.http.response import (

          Http404, HttpResponse, HttpResponseNotAllowed, StreamingHttpResponse,

          cookie,

      )

      # local Django

      from .models import LogEntry

      # try/except

      try:

          import pytz

      except ImportError:

          pytz = None

      CONSTANT = 'foo'

      class Example(object):

          # ...

* Use convenience imports whenever available. For example, do this::

      from django.views.generic import View

  instead of::

      from django.views.generic.base import View

Template style

--------------