apply black to all python scripts

docker/test/style/Dockerfile

@@ -11,6 +11,7 @@ RUN apt-get update && env DEBIAN_FRONTEND=noninteractive apt-get install --yes \
     aspell \
     curl \
     git \
+    file \
     libxml2-utils \
     moreutils \
     python3-fuzzywuzzy \

utils/check-style/check-black

@@ -4,10 +4,22 @@ set -e
 
 # We check only our code, that's why we skip contrib
 GIT_ROOT=$(git rev-parse --show-cdup)
-GIT_ROOT=${GIT_ROOT:-.}
+GIT_ROOT=${GIT_ROOT:-./}
 tmp=$(mktemp)
-# Find all *.py files in the repo except the contrib directory
-find_cmd=(find "$GIT_ROOT" -name '*.py' -not -path "$GIT_ROOT/contrib/*")
+
+# Find all *.py, *.python files and executable files without extension
+# that are determined as python scripts by 'file' util
+# in the repo except the contrib directory.
+find_cmd=(
+  find "$GIT_ROOT" -type f -not -path "${GIT_ROOT}contrib/*"
+    \(
+      -name '*.py' -or -name "*.python" -or
+        \(
+          -executable -not -name "*.*" -exec sh -c 'file {} | grep -q "Python script"' \;
+        \)
+    \)
+)
+
 if ! "${find_cmd[@]}" -exec black --check --diff {} + 1>"$tmp" 2>&1; then
   # Show the result only if some files need formatting
   cat "$tmp"
@@ -16,4 +28,5 @@ if ! "${find_cmd[@]}" -exec black --check --diff {} + 1>"$tmp" 2>&1; then
   # Automatically add changed files to stage
   "${find_cmd[@]}" -exec git add -u {} + 1>/dev/null 2>&1
 fi
+
 rm "$tmp"