Fixed error in code

len() was used twice, which produced error. Fixed that.
Also included print() statements, so that the function call actually prints the no. of vovels.

snippets/count_vowels.md

@@ -9,10 +9,10 @@ import re
 
 
 def count_vowels (str):
-    return len(len(re.findall(r'[aeiou]', str, re.IGNORECASE)))
+    return len (re.findall (r '[aeiou]', str, re.IGNORECASE))
 `` `
 
 `` `python
-count_vowels('foobar') # 3
-count_vowels('gym') # 0
+print(count_vowels('foobar')) # 3
+print(count_vowels('gym'))# 0
 ```