Update calc.py

sources/calc.py

@@ -3,7 +3,7 @@ The 'calc' library contains the 'add2' function that takes 2 values and adds
 them together. If either value is a string (or both of them are) 'add2' ensures
 they are both strings, thereby resulting in a concatenated result.
 NOTE: If a value submitted to the 'add2' function is a float, it must be done so
-in quotes (i.e. as a string).
+in quotes (i.e. as a string). update
 '''
 
 # If 'value' is not an integer, convert it to a float and failing that, a string.