Update snippet descriptions

snippets/count_by.md

@@ -5,14 +5,14 @@ tags: list,intermediate
 
 Groups the elements of a list based on the given function and returns the count of elements in each group.
 
-- Use `defaultdict()` to initialize a dictionary.
+- Use `collections.defaultdict` to initialize a dictionary.
 - Use `map()` to map the values of the given list using the given function.
 - Iterate over the map and increase the element count each time it occurs.
 
 ```py
 from collections import defaultdict
 
-def count_by(lst, fn=lambda x: x):
+def count_by(lst, fn = lambda x: x):
   count = defaultdict(int)
   for val in map(fn, lst):
     count[val] += 1
@@ -21,6 +21,7 @@ def count_by(lst, fn=lambda x: x):
 
 ```py
 from math import floor
+
 count_by([6.1, 4.2, 6.3], floor) # {6: 2, 4: 1}
 count_by(['one', 'two', 'three'], len) # {3: 2, 5: 1}
 ```