We noticed that you were trying to run the code for this unit. The code that you'd written was the following:
data = pd.concat([stock, forex, benchmark], axis=1, sort=True)
The solution code that our code evaluation engine expects was the following:
data = pd.concat([forex, benchmark, stock], axis=1, sort=True)
In the code that you'd written, `pandas` package was giving a warning, which is not properly handled by our code evaluation engine. This is something we've noted and will try to release an update soon. The evaluation engine does give code related recommendations in most cases, but this is one scenario that it doesn't handle.