diff --git a/roentgen.py b/roentgen.py
index 36cc86b..e667d30 100644
--- a/roentgen.py
+++ b/roentgen.py
@@ -4,15 +4,14 @@ Röntgen entry point.
 Author: Sergey Vartanov (me@enzet.ru).
 """
 import argparse
+import logging
 import sys
 from pathlib import Path
 from typing import List, Set
 
-import logging
 import numpy as np
 import svgwrite
 
-from roentgen.workspace import workspace
 from roentgen.constructor import Constructor
 from roentgen.flinger import Flinger
 from roentgen.grid import draw_icons
@@ -24,12 +23,13 @@ from roentgen.mapper import (
     check_level_number,
     check_level_overground,
 )
-from roentgen.osm_getter import get_osm, NetworkError
+from roentgen.osm_getter import NetworkError, get_osm
 from roentgen.osm_reader import Map, OSMReader, OverpassReader
 from roentgen.point import Point
 from roentgen.scheme import LineStyle, Scheme
-from roentgen.ui import parse_options, BoundaryBox
+from roentgen.ui import BoundaryBox, parse_options
 from roentgen.util import MinMax
+from roentgen.workspace import workspace
 
 
 def main(options) -> None:
diff --git a/roentgen/grid.py b/roentgen/grid.py
index 648a232..2f47e71 100644
--- a/roentgen/grid.py
+++ b/roentgen/grid.py
@@ -1,18 +1,18 @@
 """
 Icon grid drawing.
 """
+import logging
 from dataclasses import dataclass
 from pathlib import Path
 from typing import List, Optional, Set
 
-import logging
 import numpy as np
 from colour import Color
 from svgwrite import Drawing
 
-from roentgen.workspace import workspace
 from roentgen.icon import Icon, Shape, ShapeExtractor, ShapeSpecification
 from roentgen.scheme import NodeMatcher, Scheme
+from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
diff --git a/roentgen/mapcss.py b/roentgen/mapcss.py
index ce09855..ca11f98 100644
--- a/roentgen/mapcss.py
+++ b/roentgen/mapcss.py
@@ -1,18 +1,18 @@
 """
 MapCSS scheme creation.
 """
-from pathlib import Path
-from typing import List, Optional, Dict, TextIO
-
 import logging
+from pathlib import Path
+from typing import Dict, List, Optional, TextIO
+
 from colour import Color
 
 from roentgen import __project__, __url__
-from roentgen.workspace import workspace
 from roentgen.grid import IconCollection
 from roentgen.icon import ShapeExtractor
 from roentgen.osm_reader import STAGES_OF_DECAY
-from roentgen.scheme import Scheme, Matcher
+from roentgen.scheme import Matcher, Scheme
+from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
diff --git a/roentgen/moire_manager.py b/roentgen/moire_manager.py
index 27fef17..a9924a6 100644
--- a/roentgen/moire_manager.py
+++ b/roentgen/moire_manager.py
@@ -3,17 +3,16 @@ Moire markup extension for Röntgen.
 """
 import argparse
 from abc import ABC
-
-from moire.moire import Tag
-from moire.default import Default, DefaultHTML, DefaultMarkdown, DefaultWiki
-
-from roentgen.workspace import workspace
-from roentgen.icon import ShapeExtractor
 from pathlib import Path
-from typing import Dict, List, Any, Union
+from typing import Any, Dict, List, Union
+
 import yaml
+from moire.default import Default, DefaultHTML, DefaultMarkdown, DefaultWiki
+from moire.moire import Tag
 
 from roentgen import ui
+from roentgen.icon import ShapeExtractor
+from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
diff --git a/roentgen/osm_getter.py b/roentgen/osm_getter.py
index 68d17a0..8e79d98 100644
--- a/roentgen/osm_getter.py
+++ b/roentgen/osm_getter.py
@@ -1,12 +1,12 @@
 """
 Getting OpenStreetMap data from the web.
 """
+import logging
 import time
 import urllib
 from pathlib import Path
 from typing import Dict, Optional
 
-import logging
 import urllib3
 
 from roentgen.ui import BoundaryBox
diff --git a/roentgen/road.py b/roentgen/road.py
index f0b66a4..5d4999f 100644
--- a/roentgen/road.py
+++ b/roentgen/road.py
@@ -9,7 +9,7 @@ import svgwrite
 
 from roentgen.flinger import Flinger
 from roentgen.osm_reader import OSMNode
-from roentgen.vector import Line, angle, norm, turn_by_angle
+from roentgen.vector import Line, compute_angle, norm, turn_by_angle
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
@@ -143,7 +143,7 @@ class RoadPart:
         """
         Get an angle between line and x axis.
         """
-        return angle(self.point_2 - self.point_1)
+        return compute_angle(self.point_2 - self.point_1)
 
     def draw_normal(self, drawing: svgwrite.Drawing):
         """
diff --git a/roentgen/server.py b/roentgen/server.py
index b518896..c79bd25 100644
--- a/roentgen/server.py
+++ b/roentgen/server.py
@@ -3,9 +3,9 @@ from http.server import BaseHTTPRequestHandler, HTTPServer
 from pathlib import Path
 from typing import Optional
 
-from roentgen.workspace import workspace
 from roentgen.raster import rasterize
 from roentgen.tile import Tile
+from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
diff --git a/roentgen/taginfo.py b/roentgen/taginfo.py
index d2fa11b..3a999a7 100644
--- a/roentgen/taginfo.py
+++ b/roentgen/taginfo.py
@@ -4,22 +4,21 @@ Creating Taginfo project file.
 See https://wiki.openstreetmap.org/wiki/Taginfo/Projects
 """
 import json
+import logging
 from datetime import datetime
 from pathlib import Path
 from typing import List
 
-import logging
-
-from roentgen.workspace import workspace
 from roentgen import (
+    __author__,
+    __description__,
     __doc_url__,
+    __email__,
     __project__,
     __url__,
-    __description__,
-    __author__,
-    __email__,
 )
 from roentgen.scheme import Scheme
+from roentgen.workspace import workspace
 
 
 class TaginfoProjectFile:
diff --git a/roentgen/tile.py b/roentgen/tile.py
index 44025e2..f41c559 100644
--- a/roentgen/tile.py
+++ b/roentgen/tile.py
@@ -12,17 +12,17 @@ from typing import List, Optional, Tuple
 import numpy as np
 import svgwrite
 
-from roentgen.workspace import workspace
 from roentgen.constructor import Constructor
 from roentgen.flinger import Flinger
 from roentgen.icon import ShapeExtractor
 from roentgen.mapper import Painter
-from roentgen.osm_getter import get_osm, NetworkError
+from roentgen.osm_getter import NetworkError, get_osm
 from roentgen.osm_reader import Map, OSMReader
 from roentgen.raster import rasterize
 from roentgen.scheme import Scheme
-from roentgen.util import MinMax
 from roentgen.ui import BoundaryBox
+from roentgen.util import MinMax
+from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
@@ -241,7 +241,7 @@ class Tile:
         try:
             map_: Map = self.load_map(cache_path)
         except NetworkError as e:
-            raise NetworkError(f"Map doesn't loaded. {e.message}")
+            raise NetworkError(f"Map does not loaded. {e.message}")
 
         self.draw_for_map(map_, directory_name)
 
diff --git a/roentgen/ui.py b/roentgen/ui.py
index bd29e48..39abc5c 100644
--- a/roentgen/ui.py
+++ b/roentgen/ui.py
@@ -173,6 +173,7 @@ def add_render_arguments(render) -> None:
 
 
 def add_mapcss_arguments(mapcss) -> None:
+    """Add arguments for mapcss command."""
     mapcss.add_argument(
         "--icons",
         action=argparse.BooleanOptionalAction,
@@ -222,6 +223,10 @@ def progress_bar(
 
 @dataclass
 class BoundaryBox:
+    """
+    Rectangle that limit space on the map.
+    """
+
     left: float
     bottom: float
     right: float
diff --git a/roentgen/vector.py b/roentgen/vector.py
index 4ed14d4..56fb22b 100644
--- a/roentgen/vector.py
+++ b/roentgen/vector.py
@@ -7,7 +7,7 @@ __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
 
 
-def angle(vector: np.array):
+def compute_angle(vector: np.array):
     """
     For the given vector compute an angle between it and (1, 0) vector.  The
     result is in [0, 2π].