Error fix

src/helpers/test/knn.py

@@ -94,7 +94,7 @@ class CVSuiteTestKNN:
         This function should not be run from within the suite
         '''
         if self.trained:
-            throw("Model already trained!")
+            raise EnvironmentError("Model already trained!")
         else:
             self.knn.train(data, cv.ml.ROW_SAMPLE, tags)
             self.knn.save(output)