I received the following error, searched the community forum, and tried to implement the below fix, but to no avail. This is a recent phenomenon and I'm not sure why it's suddenly arising. The code builds and compiles properly, but fails the back test. I've attached the code for reference. Any suggestions would be much help, thanks!

Error:

Runtime Error: AttributeError : 'NoneType' object has no attribute 'Open'
at OnData
and barC.Open > barC.Close \
===
at Python.Runtime.PyObject.Invoke(PyTuple args in main.py: line 45 (Open Stack Trace)

Fix implemented but failed: