Update snippet descriptions

snippets/intersection_by.md

@@ -5,7 +5,8 @@ tags: list,function,intermediate
 
 Returns a list of elements that exist in both lists, after applying the provided function to each list element of both.
 
-- Create a `set` by applying `fn` to each element in `b`, then use list comprehension in combination with `fn` on `a` to only keep values contained in both lists.
+- Create a `set`, using `map()` to apply `fn` to each element in `b`.
+- Use a list comprehension in combination with `fn` on `a` to only keep values contained in both lists.
 
 ```py
 def intersection_by(a, b, fn):
@@ -15,5 +16,6 @@ def intersection_by(a, b, fn):
 
 ```py
 from math import floor
-intersection_by([2.1, 1.2], [2.3, 3.4],floor) # [2.1]
-```
+
+intersection_by([2.1, 1.2], [2.3, 3.4], floor) # [2.1]
+```