just make it null

Co-authored-by: Miguel <[email protected]>

Author: the-roaring

stagehand/api.py

@@ -68,7 +68,8 @@ def get_version(package_str):
         try:
             result = version(package_str)
         except PackageNotFoundError:
-            result = package_str + " not installed"
+            self.logger.error(package_str + " not installed")
+            result = None
         return result
 
     headers = {