diff --git a/pypco/pco.py b/pypco/pco.py
index c94c2a0..8a59b9a 100644
--- a/pypco/pco.py
+++ b/pypco/pco.py
@@ -536,8 +536,8 @@ def upload(self, file_path: str, **params) -> Optional[dict]:  # pylint: disable
 
     def __del__(self):
         """Close the requests session when the PCO object goes out of scope."""
-
-        self.session.close()
+        if self.session is not None:
+            self.session.close()
 
     @staticmethod
     def template(
diff --git a/tests/test_pco.py b/tests/test_pco.py
index e524868..338cb21 100644
--- a/tests/test_pco.py
+++ b/tests/test_pco.py
@@ -11,7 +11,7 @@
 
 import pypco
 from pypco.exceptions import PCORequestTimeoutException, \
-    PCORequestException, PCOUnexpectedRequestException
+    PCORequestException, PCOUnexpectedRequestException, PCOCredentialsException
 from pypco.auth_config import PCOAuthConfig
 from tests import BasePCOTestCase, BasePCOVCRTestCase
 
@@ -775,6 +775,10 @@ class TestPCOInitialization(BasePCOTestCase):
     def test_pco_initialization(self):
         """Test initializing the PCO object with various combinations of arguments."""
 
+        # region no Args:
+        with self.assertRaises(PCOCredentialsException):
+            pypco.PCO()
+
         # region Minimal Args: PAT Auth
         pco = pypco.PCO(
             'app_id',