Imrove frequencies snippet implementation (#234)

Co-authored-by: Isabelle Viktoria Maciohsek <maciv@hotmail.gr>

snippets/frequencies.md

@@ -5,16 +5,12 @@ tags: list,intermediate
 
 Returns a dictionary with the unique values of a list as keys and their frequencies as the values.
 
-- Use a `for` loop to populate a dictionary, `f`, with the unique values in `lst` as keys, adding to existing keys every time the same value is encountered.
+- Use `list.count()` to get the frequency of each unique element.
+- Use `dict()` constructor to return a dictionary with the unique elements of the list as keys and their frequencies as the values.
 
 ```py
-from functools import reduce
-
 def frequencies(lst):
-  f = {}
-  for x in lst:
-    f[x] = f[x] + 1 if x in f else 1
-  return f
+  return dict((k, lst.count(k)) for k in lst)
 ```
 
 ```py