fix: linter errors over operators.py [no ci]

src/operators.py

@@ -23,17 +23,17 @@ __email__ = "michael.maeder@hefr.ch"
 
 # file containing the operations for the calculator
 
-# addition: returns x+y 
+# addition: returns x+y
 def addition(x, y):
     return x+y
 
 
-# subtraction: returns x-y 
+# subtraction: returns x-y
 def subtraction(x, y):
     return x-y
 
 
-# multiplication: returns x*y 
+# multiplication: returns x*y
 def multiplication(x, y):
     return x*y
 
@@ -42,6 +42,6 @@ def multiplication(x, y):
 #   returns None if the divisor is zero
 #   the result might be of float type
 def division(x, y):
-    if y==0:
+    if y == 0:
         return None
     return x/y