diff --git a/homecontrol-dash.py b/homecontrol-dash.py
index 300955d..a5e083e 100755
--- a/homecontrol-dash.py
+++ b/homecontrol-dash.py
@@ -13,11 +13,12 @@ URL_BASE="http://innocence:5000"
 def get_sensors():
     ret = {}
     try:
-        url = "%s/sensor/get" % URL_BASE
+        url = f"{URL_BASE}/sensor/get"
         res = requests.get(url)
         ret = res.json()
     except Exception as ex:
-        print('Exception Type:%s, args:\n%s' % (type(ex).__name__, ex.args))
+        print(f"Exception Type: {type(ex).__name__}, args:\n{ex.args}")
+
     return ret
 
 
@@ -25,15 +26,20 @@ def get_values(sensorId, min_ts, max_ts, limit):
     ret = {}
     if sensorId:
         try:
-            url = "%s/sensor/get_values/%s?min_ts=%s&max_ts=%s&limit=%s" % (URL_BASE,
-                    sensorId, min_ts, max_ts, limit)
+            url = f"{URL_BASE}/sensor/get_values/{sensorId}?min_ts={min_ts}&max_ts={max_ts}&limit={limit}"
             # print(url)
             res = requests.get(url)
             ret = res.json()[sensorId]
         except Exception as ex:
-            print('Exception Type:%s, args:\n%s' % (type(ex).__name__, ex.args))
+            print(f"Exception Type: {type(ex).__name__}, args:\n{ex.args}")
     return ret
 
+def pTime(value, fmt="%Y/%m/%d %H:%M"):
+    if value > 0:
+        return time.strftime(fmt, time.localtime(float(value)))
+    else:
+        return 0
+
 
 sensors = get_sensors()
 sensor = next(iter(sensors), None)
@@ -108,7 +114,7 @@ def update_slider_min(sensorId):
         min_ts = int(res["values"][0]["ts"])
         sensorType = res["sensorType"]
 
-    # print("min: [%f [%f] %f]" % (min_ts, min_ts, max_ts))
+    # print(f"min: [{min_ts} [{cur_ts}] {max_ts}]"
     return min_ts, cur_ts, max_ts
 
 
@@ -116,8 +122,7 @@ def update_slider_min(sensorId):
         Output('slider-min-txt', 'children'),
         [Input('slider-min', 'value')])
 def update_slider_min_txt(value):
-    return "From: %s" % (time.strftime("%Y/%m/%d %H:%M", time.localtime(float(value))) if
-            value > 0 else 0)
+    return f"From: {pTime(value)}"
 
 @app.callback(
         [Output('slider-max', 'min'), Output('slider-max', 'value'),
@@ -132,7 +137,7 @@ def update_slider_max(sensorId):
         min_ts = int(res["values"][0]["ts"])
         sensorType = res["sensorType"]
 
-    # print("max: [%f [%f] %f]" % (min_ts, max_ts, max_ts))
+    # print(f"max: [{min_ts} [{max_ts}] {max_ts}]"
     return min_ts, max_ts, max_ts
 
 
@@ -140,14 +145,14 @@ def update_slider_max(sensorId):
         Output('slider-max-txt', 'children'),
         [Input('slider-max', 'value')])
 def update_slider_max_txt(value):
-    return "To: %s" % (time.strftime("%Y/%m/%d %H:%M", time.localtime(float(value))))
+    return f"To: {pTime(value)}"
 
 
 @app.callback(
         Output('slider-limit-txt', 'children'),
         [Input('slider-limit', 'value')])
 def update_slider_limit_txt(value):
-    return "Limit: %s" % (value if value > 0 else None)
+    return f"Limit: {value if value > 0 else None}"
 
 
 @app.callback(
@@ -161,7 +166,7 @@ def update_graph_sensor_values(sensorId, min_ts, max_ts, limit):
     if "values" in res:
         v = res["values"]
         s = res["sensorType"]
-        x = [time.strftime("%m%d-%H%M", time.localtime(float(v[i]["ts"]))) for i in range(len(v))]
+        x = [pTime(v[i]["ts"], fmt="%m%d-%H%M") for i in range(len(v))]
         if s == "luminance":
             y = [log10(v[i]["value"]/5+1) for i in range(len(v))]
         else:
@@ -171,8 +176,8 @@ def update_graph_sensor_values(sensorId, min_ts, max_ts, limit):
         x = [0]
         y = [0]
     return {
-        'data': [ {'x': x, 'y': y, 'mode': 'line', 'name': "%s" % (s)} ],
-        'layout': { 'title': 'Data for sensor: %s (%d elements)' % (s, len(x)) }
+        'data': [ {'x': x, 'y': y, 'mode': 'line', 'name': f'{s}'} ],
+        'layout': { 'title': f'Data for sensor: {s} ({len(x)} elements)' }
     }
 
 if __name__ == '__main__':