diff --git a/examples/docker-flask/app.py b/examples/docker-flask/app.py
index 6de0de8..7febda9 100644
--- a/examples/docker-flask/app.py
+++ b/examples/docker-flask/app.py
@@ -7,14 +7,16 @@ from io import BytesIO
 # Initialize Flask app
 app = Flask(__name__)
 
-@app.route('/', methods=['GET'])
+
+@app.route("/", methods=["GET"])
 def do_print():
-    #p = Usb(0x04b8, 0x0e28, 0)
-    p = CupsPrinter(host='localhost', port=631, printer_name='TM-T20III')
+    # p = Usb(0x04b8, 0x0e28, 0)
+    p = CupsPrinter(host="localhost", port=631, printer_name="TM-T20III")
     p.text("Hello World\n")
     p.cut()
     p.close()
     return "OK"
 
-if __name__ == '__main__':
-    app.run(debug=False, host='0.0.0.0', port=9999)
+
+if __name__ == "__main__":
+    app.run(debug=False, host="0.0.0.0", port=9999)