Multiplication support

We decided to just implment two-argument
multiplication, because users don't need anything
more complicated yet

src/calc.py

@@ -18,3 +18,14 @@ def sub(a, b):
     ```
     """
     return a - b
+
+
+def mult(a, b):
+    """
+    Multiply some numbers
+
+    ```py
+    mult(8, 3) # 24
+    ```
+    """
+    return a * b

src/calc_test.py

@@ -1,5 +1,5 @@
 import unittest
-from calc import add, sub 
+from calc import add, sub, mult
 
 class TestStringMethods(unittest.TestCase):
 
@@ -11,5 +11,9 @@ def test_sub_2arg(self):
         # Make sure 4 - 3 = 1
         self.assertEqual(sub(4, 3), 1, 'subtracting three from four')
 
+    def test_mult_2arg(self):
+        # Make sure 4 * 3 = 12
+        self.assertEqual(mult(4, 3), 12, 'multiplying three and four')
+
 if __name__ == '__main__':
     unittest.main()

src/main.py

@@ -2,7 +2,6 @@
 
 def main(): 
     x = add(3, sub(7, 2))
-    x = x/2
     return x
 
 print('Result = {}'.format(main()))