diff --git a/samcli/commands/local/lib/swagger/parser.py b/samcli/commands/local/lib/swagger/parser.py
index 9c46e0c631..68ada78024 100644
--- a/samcli/commands/local/lib/swagger/parser.py
+++ b/samcli/commands/local/lib/swagger/parser.py
@@ -81,7 +81,7 @@ def get_authorizers(self, event_type: str = Route.API) -> Dict[str, Authorizer]:
         authorizers: Dict[str, Authorizer] = {}
 
         authorizer_dict = {}
-        document_version = self.swagger.get(SwaggerParser._SWAGGER) or self.swagger.get(SwaggerParser._OPENAPI) or ""
+        document_version = self._get_document_version()
 
         if document_version.startswith(SwaggerParser._2_X_VERSION):
             LOG.debug("Parsing Swagger document using 2.0 specification")
@@ -240,6 +240,19 @@ def _get_lambda_identity_sources(
 
         return identity_sources
 
+    def _get_document_version(self) -> str:
+        """
+        Helper method to fetch the Swagger document version
+
+        Returns
+        -------
+        str
+            A string representing a version, blank if not found
+        """
+        document_version = self.swagger.get(SwaggerParser._SWAGGER) or self.swagger.get(SwaggerParser._OPENAPI) or ""
+
+        return str(document_version)
+
     def get_default_authorizer(self, event_type: str) -> Union[str, None]:
         """
         Parses the body definition to find root level Authorizer definitions
@@ -254,7 +267,7 @@ def get_default_authorizer(self, event_type: str) -> Union[str, None]:
         Union[str, None]
             Returns the name of the authorizer, if there is one defined, otherwise None
         """
-        document_version = self.swagger.get(SwaggerParser._SWAGGER) or self.swagger.get(SwaggerParser._OPENAPI) or ""
+        document_version = self._get_document_version()
         authorizers = self.swagger.get(SwaggerParser._SWAGGER_SECURITY, [])
 
         if not authorizers:
diff --git a/tests/unit/commands/local/lib/swagger/test_parser.py b/tests/unit/commands/local/lib/swagger/test_parser.py
index 84ce8899de..d854ca595e 100644
--- a/tests/unit/commands/local/lib/swagger/test_parser.py
+++ b/tests/unit/commands/local/lib/swagger/test_parser.py
@@ -1022,3 +1022,21 @@ def test_invalid_identity_source_throws_exception(self):
 
         with self.assertRaises(InvalidSecurityDefinition):
             parser._get_lambda_identity_sources(Mock(), "request", Route.API, properties, auth_properties)
+
+
+class TestGetDocumentVersion(TestCase):
+    @parameterized.expand(
+        [
+            ({"swagger": "2.0"}, "2.0"),
+            ({"swagger": 2.0}, "2.0"),
+            ({"openapi": "3.0"}, "3.0"),
+            ({"openapi": 3.0}, "3.0"),
+            ({"not valid": 3.0}, ""),
+            ({}, ""),
+        ]
+    )
+    def test_get_document_version(self, swagger_doc, expected_output):
+        parser = SwaggerParser(Mock(), swagger_doc)
+        output = parser._get_document_version()
+
+        self.assertEqual(output, expected_output)