chore: update examples

examples/01_simple_type_checking/02_simple_types.midas

@@ -1,6 +1,6 @@
-type Meter(float)
-type Second(float)
-type MeterPerSecond(float)
+type Meter = float
+type Second = float
+type MeterPerSecond = float
 
 extend Meter {
     op __add__(Meter) -> Meter

examples/01_simple_type_checking/03_control_flow.py

@@ -4,13 +4,20 @@ def minimum(x: int, y: int):
     else:
         return y
 
+
 a = 15
 b = 72
 c = minimum(a, b)
 
+
 def factorial(n: int) -> int:
     if n <= 1:
         return 1
     return n * factorial(n - 1)
 
-category = "Category 1" if a < 10 else "Category 2"
+
+category = "Category 1" if a < 10 else "Category 2"
+
+
+def foo() -> None:
+    pass