Minor warning in Apex driver, Including their manual

Author: thomaslima

lightlab/equipment/lab_instruments/Apex_AP2440A_OSA.py

@@ -212,7 +212,7 @@ def spectrum(self, average_count=1):
             self.triggerAcquire()
             nm, dbm = self.transferData()
 
-            if i is 0:
+            if i == 0:
                 dbmAvg = dbm / average_count
             else:
                 dbmAvg = dbmAvg + dbm / average_count