added assert for scoreresults

Added an assert with an error message.
On line 843 sc is created with a double list comprehension, by adding an assert statement asserting whether scoreresults element 0 is a list we check that the double list comprehension can go ahead. The AssertionError prints a short text and the scoreresults - often you will see that its an empty list indicating that your integration has failed.

tldr assert error to get understandable error message