fix style issue found by flake8

src/nominatim_db/utils/centroid.py

@@ -10,6 +10,7 @@ Functions for computation of centroids.
 from typing import Tuple, Any
 from collections.abc import Collection
 
+
 class PointsCentroid:
     """ Centroid computation from single points using an online algorithm.
         More points may be added at any time.
@@ -32,11 +33,9 @@ class PointsCentroid:
         return (float(self.sum_x/self.count)/10000000,
                 float(self.sum_y/self.count)/10000000)
 
-
     def __len__(self) -> int:
         return self.count
 
-
     def __iadd__(self, other: Any) -> 'PointsCentroid':
         if isinstance(other, Collection) and len(other) == 2:
             if all(isinstance(p, (float, int)) for p in other):

src/nominatim_db/utils/url_utils.py

@@ -7,7 +7,7 @@
 """
 Helper functions for accessing URL.
 """
-from typing import IO
+from typing import IO  # noqa
 import logging
 import urllib.request as urlrequest
 
@@ -15,6 +15,7 @@ from ..version import NOMINATIM_VERSION
 
 LOG = logging.getLogger()
 
+
 def get_url(url: str) -> str:
     """ Get the contents from the given URL and return it as a UTF-8 string.
 
@@ -24,7 +25,7 @@ def get_url(url: str) -> str:
 
     try:
         request = urlrequest.Request(url, headers=headers)
-        with urlrequest.urlopen(request) as response: # type: IO[bytes]
+        with urlrequest.urlopen(request) as response:  # type: IO[bytes]
             return response.read().decode('utf-8')
     except Exception:
         LOG.fatal('Failed to load URL: %s', url)