Remove dublicate printers from the list

README.md

@@ -195,6 +195,7 @@ your setup. When the Get Printer Info switch is set ON, the driver calls each pr
 once a minute and collects some info about it. It calls the printer configured
 in the settings as well as all printers it finds in the label templates.
 In case a printer is unreachable, an error message is shown.
+
 ![Printer Info](https://github.com/SergeoLacruz/inventree-zebra-plugin/blob/master/pictures/printer_info.png)
 
 ## How it works

inventree_zebra/zebra_plugin.py

@@ -242,6 +242,7 @@ def print_label(self, **kwargs):
     def get_generated_file(self, **kwargs):
         return self.preview_result
 
+# -----------------------------------------------------------------------------
     def ping_printer(self, *args, **kwargs):
 
         printer_data = []
@@ -342,7 +343,8 @@ def collect_all_ipprinter(self):
         for template in all_templates:
             try:
                 if 'ip_address' in template.metadata:
-                    all_printer.append(template.metadata['ip_address'])
+                    if template.metadata['ip_address'] not in all_printer:
+                        all_printer.append(template.metadata['ip_address'])
             except Exception:
                 pass
         return all_printer