fixed + completed type hints

vec.py

@@ -5,8 +5,8 @@ from math import sqrt
 
 class Vec:
     def __init__(self, x: float = 0, y: float = 0) -> None:
-        self.x = x
-        self.y = y
+        self.x: float = x
+        self.y: float = y
     
     def __add__(self, v: Vec) -> Vec:
         return Vec(self.x+v.x, self.y+v.y)
@@ -25,5 +25,6 @@ class Vec:
     
     def norm(self) -> Vec:
         mag = self.mag()
-        if mag == 0: return Vec()
-        return self/mag
+        if mag == 0:
+            return Vec()
+        return self / mag