Properly close serial connection

main.py

@@ -12,7 +12,7 @@
 # Configuration and filenames
 ###########################
 try:
-    VERSION = "1.0.1"
+    VERSION = "1.0.2"
 
     # Get unique hardware id of Raspberry Pi
     # See: https://www.raspberrypi.com/documentation/computers/config_txt.html#the-serial-number-filter
@@ -274,6 +274,11 @@ def get_cpu_serial():
 except Exception as e:
     logging.warning("Could not get GPS coordinates: %s", str(e))
 
+try:
+    sim7600.close()
+except Exception as e:
+    logging.warning("Could not close serial connection with 4G module: %s", str(e))
+
 ###########################
 # Uploading sensor data
 ###########################

sim7600x.py

@@ -111,6 +111,13 @@ def stop_gps_session(self):
         except Exception as e:
             logging.error("Could not stop GPS session: %s", str(e))
 
+    def close(self):
+        '''Close the serial connection.'''
+        try:
+            self.ser.close()
+        except Exception as e:
+            logging.error("Could not close serial connection: %s", str(e))
+
 if __name__ == "__main__":
     logging.basicConfig(level=logging.INFO)
     sim7600x = SIM7600X()