Sort imports with isort

Keep imports alphabetically sorted and their order homogeneous across
Python source files.

The isort project has more feature and is more active than the
flake8-import-order plugin.

Most issues caught were simply import ordering from the same module.
Where imports were purposefully placed out of order, tag with
isort:skip.

6 files changed, 13 insertions, 21 deletions

diff --git a/sphinx/transforms/__init__.py b/sphinx/transforms/__init__.py
index beb983f2a..f854f1772 100644
--- a/sphinx/transforms/__init__.py
+++ b/sphinx/transforms/__init__.py
@@ -23,8 +23,7 @@ from sphinx import addnodes
 from sphinx.config import Config
 from sphinx.deprecation import RemovedInSphinx40Warning, deprecated_alias
 from sphinx.locale import _, __
-from sphinx.util import docutils
-from sphinx.util import logging
+from sphinx.util import docutils, logging
 from sphinx.util.docutils import new_document
 from sphinx.util.i18n import format_date
 from sphinx.util.nodes import NodeMatcher, apply_source_workaround, is_smartquotable
@@ -401,9 +400,8 @@ class ManpageLink(SphinxTransform):
             node.attributes.update(info)
 
 
-from sphinx.domains.citation import (  # NOQA
-    CitationDefinitionTransform, CitationReferenceTransform
-)
+from sphinx.domains.citation import CitationDefinitionTransform  # NOQA
+from sphinx.domains.citation import CitationReferenceTransform  # NOQA
 
 deprecated_alias('sphinx.transforms',
                  {
diff --git a/sphinx/transforms/compact_bullet_list.py b/sphinx/transforms/compact_bullet_list.py
index 1cde3b1f0..e30efa92b 100644
--- a/sphinx/transforms/compact_bullet_list.py
+++ b/sphinx/transforms/compact_bullet_list.py
@@ -8,8 +8,7 @@
     :license: BSD, see LICENSE for details.
 """
 
-from typing import Any, Dict, List
-from typing import cast
+from typing import Any, Dict, List, cast
 
 from docutils import nodes
 from docutils.nodes import Node
diff --git a/sphinx/transforms/i18n.py b/sphinx/transforms/i18n.py
index c935ab195..bffcb511d 100644
--- a/sphinx/transforms/i18n.py
+++ b/sphinx/transforms/i18n.py
@@ -20,18 +20,18 @@ from docutils.utils import relative_path
 from sphinx import addnodes
 from sphinx.config import Config
 from sphinx.domains.std import make_glossary_term, split_term_classifiers
-from sphinx.locale import __, init as init_locale
+from sphinx.locale import __
+from sphinx.locale import init as init_locale
 from sphinx.transforms import SphinxTransform
-from sphinx.util import split_index_msg, logging, get_filetype
+from sphinx.util import get_filetype, logging, split_index_msg
 from sphinx.util.i18n import docname_to_domain
-from sphinx.util.nodes import (
-    LITERAL_TYPE_NODES, IMAGE_TYPE_NODES, NodeMatcher,
-    extract_messages, is_pending_meta, traverse_translatable_index,
-)
+from sphinx.util.nodes import (IMAGE_TYPE_NODES, LITERAL_TYPE_NODES, NodeMatcher,
+                               extract_messages, is_pending_meta, traverse_translatable_index)
 
 if False:
     # For type annotation
     from typing import Type  # for python3.5.1
+
     from sphinx.application import Sphinx
 
 
diff --git a/sphinx/transforms/post_transforms/__init__.py b/sphinx/transforms/post_transforms/__init__.py
index 6633d6434..f9feab2a6 100644
--- a/sphinx/transforms/post_transforms/__init__.py
+++ b/sphinx/transforms/post_transforms/__init__.py
@@ -8,8 +8,7 @@
     :license: BSD, see LICENSE for details.
 """
 
-from typing import Any, Dict, List, Tuple, Type
-from typing import cast
+from typing import Any, Dict, List, Tuple, Type, cast
 
 from docutils import nodes
 from docutils.nodes import Element
@@ -25,7 +24,6 @@ from sphinx.util import logging
 from sphinx.util.docutils import SphinxTranslator
 from sphinx.util.nodes import process_only_nodes
 
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/sphinx/transforms/post_transforms/code.py b/sphinx/transforms/post_transforms/code.py
index 2012d6e11..d306b5c80 100644
--- a/sphinx/transforms/post_transforms/code.py
+++ b/sphinx/transforms/post_transforms/code.py
@@ -20,7 +20,6 @@ from sphinx.application import Sphinx
 from sphinx.ext import doctest
 from sphinx.transforms import SphinxTransform
 
-
 HighlightSetting = NamedTuple('HighlightSetting', [('language', str),
                                                    ('force', bool),
                                                    ('lineno_threshold', int)])
diff --git a/sphinx/transforms/post_transforms/images.py b/sphinx/transforms/post_transforms/images.py
index 949c09dde..4865aa615 100644
--- a/sphinx/transforms/post_transforms/images.py
+++ b/sphinx/transforms/post_transforms/images.py
@@ -18,12 +18,10 @@ from docutils import nodes
 from sphinx.application import Sphinx
 from sphinx.locale import __
 from sphinx.transforms import SphinxTransform
-from sphinx.util import epoch_to_rfc1123, rfc1123_to_epoch, sha1
-from sphinx.util import logging, requests
-from sphinx.util.images import guess_mimetype, get_image_extension, parse_data_uri
+from sphinx.util import epoch_to_rfc1123, logging, requests, rfc1123_to_epoch, sha1
+from sphinx.util.images import get_image_extension, guess_mimetype, parse_data_uri
 from sphinx.util.osutil import ensuredir, movefile
 
-
 logger = logging.getLogger(__name__)
 
 MAX_FILENAME_LEN = 32