Update imports

Update imports in rads_to_degrees
Update imports and formatting in gcd
Update imports in degrees_to_rads
Update import in snake

snippets/rads_to_degrees.md

@@ -8,13 +8,13 @@ Converts an angle from radians to degrees.
 Use `math.pi` and the radian to degree formula to convert the angle from radians to degrees.
 
 ```py
-import math
+from math import pi
 
 def rads_to_degrees(rad):
   return (rad * 180.0) / math.pi
 ```
 
 ```py
-import math
+from math import pi
 rads_to_degrees(math.pi / 2) # 90.0
 ```