examples: add get_country_list and add_invoice

examples/get_country_list.py

@@ -0,0 +1,18 @@
+"""
+This script retrieves and prints the list of countries using the SuperFaktura API.
+"""
+
+from pprint import pprint
+
+from superfaktura.utils.country import country_list
+
+
+def main():
+    """
+    Main function to retrieve and print the list of countries using the SuperFaktura API.
+    """
+    pprint(country_list())
+
+
+if __name__ == "__main__":
+    main()