tracks/python/exercises/complex-numbers/example.py in trackler-2.2.1.40 vs tracks/python/exercises/complex-numbers/example.py in trackler-2.2.1.41

@@ -10,11 +10,11 @@
         r = self.real + other.real
         i = self.imaginary + other.imaginary
         return ComplexNumber(r, i)
 
     def mul(self, other):
-        r = self.real * other.real
-        i = self.imaginary * other.imaginary
+        r = self.real * other.real - self.imaginary * other.imaginary
+        i = self.real * other.imaginary + self.imaginary * other.real
         return ComplexNumber(r, i)
 
     def sub(self, other):
         r = self.real - other.real
         i = self.imaginary - other.imaginary