diff --git a/dockstat.py b/dockstat.py
index 0786610..30ae617 100644
--- a/dockstat.py
+++ b/dockstat.py
@@ -16,8 +16,8 @@ import numpy
 from prometheus_client import CollectorRegistry  # type: ignore[import]
 from prometheus_client import Gauge, MetricsHandler, generate_latest
 
-LISTEN_PORT = int(os.environ.get('DOCKSTAT_LISTEN_PORT', 8080))
-HEALTHY_STR = 'healthy'
+LISTEN_PORT = int(os.environ.get("DOCKSTAT_LISTEN_PORT", 8080))
+HEALTHY_STR = "healthy"
 
 
 class HTTPHandler(MetricsHandler):  # type: ignore[misc]
@@ -36,18 +36,18 @@ class HTTPHandler(MetricsHandler):  # type: ignore[misc]
         """
         Handle GET requests
         """
-        if self.path == '/metrics':
+        if self.path == "/metrics":
             try:
                 self._metrics()
             except docker.errors.NotFound:
                 pass
 
-        if self.path == '/healthcheck':
+        if self.path == "/healthcheck":
             if not healthy():
-                print('ERROR: Check requirements')
-                self._respond(500, 'ERR')
+                print("ERROR: Check requirements")
+                self._respond(500, "ERR")
 
-            self._respond(200, 'OK')
+            self._respond(200, "OK")
 
     def _respond(self, status: int, message: str) -> None:
         """
@@ -71,40 +71,40 @@ class HTTPHandler(MetricsHandler):  # type: ignore[misc]
         Handle the request for metrics
         """
         if not healthy:
-            print('ERROR: Check requirements')
-            self._respond(500, 'Server not configured correctly')
+            print("ERROR: Check requirements")
+            self._respond(500, "Server not configured correctly")
             return
 
         registry = CollectorRegistry()
 
         health_gauge = Gauge(
-            'container_inspect_state_health_status',
+            "container_inspect_state_health_status",
             "Container's healthcheck value (binary)",
-            labelnames=['id', 'name', 'value'],
+            labelnames=["id", "name", "value"],
             registry=registry,
         )
         status_gauge = Gauge(
-            'container_inspect_state_running',
+            "container_inspect_state_running",
             "Container's running state (binary)",
-            labelnames=['id', 'name'],
+            labelnames=["id", "name"],
             registry=registry,
         )
         started_at_gauge = Gauge(
-            'container_inspect_state_started_at',
+            "container_inspect_state_started_at",
             "Container's start time (int)",
-            labelnames=['id', 'name'],
+            labelnames=["id", "name"],
             registry=registry,
         )
         exit_code_gauge = Gauge(
-            'container_inspect_state_exit_code',
+            "container_inspect_state_exit_code",
             "Container's exit code (int)",
-            labelnames=['id', 'name'],
+            labelnames=["id", "name"],
             registry=registry,
         )
         alert_threshold_gauge = Gauge(
-            'container_inspect_downtime_alert_threshold',
+            "container_inspect_downtime_alert_threshold",
             "Container's downtime alert threshold in seconds (int)",
-            labelnames=['id', 'name'],
+            labelnames=["id", "name"],
             registry=registry,
         )
 
@@ -112,16 +112,16 @@ class HTTPHandler(MetricsHandler):  # type: ignore[misc]
             try:
                 data = self.docker_api.inspect_container(container.id)
             except docker.errors.NotFound:
-                print(f'WARNING: Container {container.id} does not exist. Skipping.')
+                print(f"WARNING: Container {container.id} does not exist. Skipping.")
                 continue
 
-            running = bool(data['State']['Running'])
-            started_at = data['State']['StartedAt']
-            exit_code = int(data['State']['ExitCode'])
+            running = bool(data["State"]["Running"])
+            started_at = data["State"]["StartedAt"]
+            exit_code = int(data["State"]["ExitCode"])
             alert_threshold = int(
-                data['Config']['Labels'].get('io.prometheus.alert.downtime', 3600)
+                data["Config"]["Labels"].get("io.prometheus.alert.downtime", 3600)
             )
-            starttime: numpy.longlong = numpy.datetime64(started_at, 's').astype('long')
+            starttime: numpy.longlong = numpy.datetime64(started_at, "s").astype("long")
 
             status_gauge.labels(
                 container.id,
@@ -141,7 +141,7 @@ class HTTPHandler(MetricsHandler):  # type: ignore[misc]
             ).set(alert_threshold)
 
             try:
-                health_str = data['State']['Health']['Status']
+                health_str = data["State"]["Health"]["Status"]
                 health_gauge.labels(
                     container.id,
                     container.name,
@@ -162,12 +162,12 @@ def healthy() -> bool:
     """
     return all(
         [
-            os.path.exists('/var/run/docker.sock'),
+            os.path.exists("/var/run/docker.sock"),
         ]
     )
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
 
     def cli_parse() -> argparse.Namespace:
         """
@@ -179,10 +179,10 @@ if __name__ == '__main__':
         parser = argparse.ArgumentParser()
 
         parser.add_argument(
-            '-H',
-            '--healthcheck',
-            action='store_true',
-            help='Simply exit with 0 for healthy or 1 when unhealthy',
+            "-H",
+            "--healthcheck",
+            action="store_true",
+            help="Simply exit with 0 for healthy or 1 when unhealthy",
         )
 
         return parser.parse_args()
@@ -197,11 +197,11 @@ if __name__ == '__main__':
             # Invert the sense of 'healthy' for Unix CLI usage
             return not healthy()
 
-        print(f'Starting web server on port {LISTEN_PORT}')
+        print(f"Starting web server on port {LISTEN_PORT}")
         try:
-            HTTPServer(('', LISTEN_PORT), HTTPHandler).serve_forever()
+            HTTPServer(("", LISTEN_PORT), HTTPHandler).serve_forever()
         except KeyboardInterrupt:
-            print('Exiting')
+            print("Exiting")
 
         return 0