old_ip if not exist || empty

init.py

@@ -12,17 +12,20 @@ while True:
         # lo crea
         f = open("old_ip.txt", "a")
         # escribe la palabra ip
-        f.write("ip")
+        f.write("ip nueva")
         f.close()
 
+    # si existe y esta vacia
     with open("old_ip.txt", "r") as f:
         contenido = f.read()
-        if contenido != '':
-            old_ip = f.readlines()[0].strip()
-        else:
+        if contenido == '':
             f = open("old_ip.txt", "w")
-            f.write("ip")
+            f.write("ip vacia")
             f.close()
+
+    # si existe y tiene algo escrito
+    with open("old_ip.txt", "r") as f:
+        old_ip = f.readlines()[0].strip()
         if ip != old_ip:
             # son distintas
             f = open("old_ip.txt", "w")