diff --git a/pocket_ic/pocket_ic.py b/pocket_ic/pocket_ic.py
index b0f7544..128279c 100644
--- a/pocket_ic/pocket_ic.py
+++ b/pocket_ic/pocket_ic.py
@@ -82,7 +82,10 @@ def get_subnet_of_canister(self, canister_id: ic.Principal) -> Optional[ic.Princ
             "canister_id": base64.b64encode(canister_id.bytes).decode()
         }
         res = self._instance_post("read/canister_exists", payload)
-        return ic.Principal.from_str(res["subnet_id"]) if res is not None else None
+        if res:
+            b = base64.b64decode(res["canister_id"])
+            return ic.Principal(b)
+        return None
 
     def check_canister_exists(self, canister_id: ic.Principal) -> bool:
         """Check whether the provided canister exists.
@@ -240,7 +243,7 @@ def create_canister(self, settings: Optional[list] = None, subnet: Optional[ic.P
             {"type": record, "value": {"settings": settings if settings else []}}
         ]
 
-        request_result = self._canister_call("update/execute_ingress_message", None, {"SubnetId": subnet.to_str()} if subnet else None, "provisional_create_canister_with_cycles", ic.encode(payload))
+        request_result = self._canister_call("update/execute_ingress_message", None, {"SubnetId": list(bytes(subnet.bytes))} if subnet else None, "provisional_create_canister_with_cycles", ic.encode(payload))
         candid = ic.decode(
             bytes(request_result), Types.Record({"canister_id": Types.Principal})
         )
diff --git a/tests/pocket_ic_test.py b/tests/pocket_ic_test.py
index 5c14d23..4c2c830 100644
--- a/tests/pocket_ic_test.py
+++ b/tests/pocket_ic_test.py
@@ -24,10 +24,17 @@ def tearDown(self) -> None:
         del self.pic
         return super().tearDown()
     
-    def test_basic_multi_subnet(self):
+    def test_install_canister_on_subnet(self):
         config = [NNS, STANDARD]
         pic = PocketIC(config)
-        id = pic.create_canister()
+        
+        canister_1 = pic.create_canister(subnet=ic.Principal.from_str("fscpm-uiaaa-aaaaa-aaaap-yai"))
+        canister_2 = pic.create_canister(subnet=ic.Principal.from_str("yndj2-3ybaa-aaaaa-aaaap-yai"))
+
+        subnet_1 = pic.get_subnet_of_canister(canister_1)
+        print(subnet_1)
+        subnet_2 = pic.get_subnet_of_canister(canister_2)
+        print(subnet_2)
 
     def test_set_get_stable_memory_no_compression(self):
         canister_id = self.pic.create_canister()
@@ -76,7 +83,7 @@ def test_canister_exists(self):
         self.assertEqual(self.pic.check_canister_exists(canister_id), True)
 
     def test_canister_exists_negative(self):
-        canister_id = ic.Principal.from_str("rwlgt-iiaaa-aaaaa-aaaaa-cai")
+        canister_id = ic.Principal.anonymous()
         self.assertEqual(self.pic.check_canister_exists(canister_id), False)
 
     def test_cycles_balance(self):