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/degrees_to_rads.md

@@ -8,10 +8,10 @@ Converts an angle from degrees to radians.
 Use `math.pi` and the degrees to radians formula to convert the angle from degrees to radians.
 
 ```py
-import math
+from math import pi
 
 def degrees_to_rads(deg):
-  return (deg * math.pi) / 180.0
+  return (deg * pi) / 180.0
 ```
 
 ```py

snippets/gcd.md

@@ -5,16 +5,16 @@ tags: math,beginner
 
 Calculates the greatest common divisor of a list of numbers.
 
-Use `reduce()` and `math.gcd` over the given list.
+Use `functools.reduce()` and `math.gcd()` over the given list.
 
 ```py
 from functools import reduce
-import math
+from math import gcd
 
 def gcd(numbers):
-  return reduce(math.gcd, numbers)
+  return reduce(gcd, numbers)
 ```
 
 ```py
-gcd([8,36,28]) # 4
+gcd([8, 36, 28]) # 4
-```
+```

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
 ```

snippets/snake.md

@@ -8,11 +8,12 @@ Converts a string to snake case.
 Break the string into words and combine them adding `_` as a separator, using a regexp.
 
 ```py
-import re
+from re import sub
 
 def snake(s):
-  return '_'.join(re.sub('([A-Z][a-z]+)', r' \1',
+  return '_'.join(
-    re.sub('([A-Z]+)', r' \1',
+    sub('([A-Z][a-z]+)', r' \1',
+    sub('([A-Z]+)', r' \1',
     s.replace('-', ' '))).split()).lower()
 ```