Added example on 2d lists and changed format (#23665)

updated the code format along with an example of 2d list.

guide/english/python/len-function/index.md

@@ -12,19 +12,32 @@ It takes one argument, `x`. This argument may be a sequence (such as a string, b
 This function returns the number of elements in the argument which is passed to the `len()` function.
 
 ## Code Sample
-
+```py
-    list1 = [123, 'xyz', 'zara'] # list
+    >>> list1 = [123, 'xyz', 'zara'] # list
-    print(len(list1)) # prints 3 as there are 3 elements in the list1
+    >>> print(len(list1)) # prints 3 as there are 3 elements in the list1
-
+    3
-    str1 = 'basketball' # string
+```
-    print(len(str1)) # prints 10 as the str1 is made of 10 characters
+```py
-
+    >>> str1 = 'basketball' # string
-    tuple1 = (2, 3, 4, 5) # tuple 
+    >>> print(len(str1)) # prints 10 as the str1 is made of 10 characters
-    print(len(tuple1)) # prints 4 as there are 4 elements in the tuple1
+    10
-
+```
-    dict1 = {'name': 'John', 'age': 4, 'score': 45} # dictionary
+```py
-    print(len(dict1)) # prints 3 as there are 3 key and value pairs in the dict1
+    >>> tuple1 = (2, 3, 4, 5) # tuple 
+    >>> print(len(tuple1)) # prints 4 as there are 4 elements in the tuple1
+    4
+```
+```py
+    >>> dict1 = {'name': 'John', 'age': 4, 'score': 45} # dictionary
+    >>> print(len(dict1)) # prints 3 as there are 3 key and value pairs in the dict1
+    3
+```   
+```py
+    >>> d2=[[1,2,3],[3,4,5],[5,6,7,2]] # 2 dimensional list or a list of lists
+    >>> print(len(d2)) #prints 3 because there are 3 different lists in the outer list.
+    3
+```    
 
 ![:rocket:](//forum.freecodecamp.com/images/emoji/emoji_one/rocket.png?v=2 ":rocket:") <a href='https://repl.it/CUmt/15' target='_blank' rel='nofollow'>Run Code</a>
 
-<a href='https://docs.python.org/3/library/functions.html#len' target='_blank' rel='nofollow'>Official Docs</a>
+<a href='https://docs.python.org/3/library/functions.html#len' target='_blank' rel='nofollow'>Official Docs</a>