docs: Add missing commas to python tab in intro.md (#269)

* Add missing commas to python tab in intro.md 

* add constructs import to intro.md

website/docs/intro.md

@@ -114,6 +114,9 @@ We will now use [***DataLakeStorage***](constructs/library/02-Storage/03-data-la
     import aws_cdk as cdk
     import aws_dsf as dsf
 
+    from constructs import Construct
+
+
     class DsfExampleStack(cdk.Stack):
 
       def __init__(self, scope: cdk.App, construct_id: str, **kwargs) -> None:
@@ -123,13 +126,13 @@ We will now use [***DataLakeStorage***](constructs/library/02-Storage/03-data-la
           self,
           bronze_name="my-bronze",
           bronze_infrequent_access_delay="90",
-          bronze_archive_delay="180"
+          bronze_archive_delay="180",
           silver_name="my-silver",
           silver_infrequent_access_delay="180",
-          silver_archive_delay="360"
+          silver_archive_delay="360",
           gold_name="my-gold",
           gold_infrequent_access_delay="180",
-          gold_archive_delay="360"
+          gold_archive_delay="360",
           removal_policy=cdk.RemovalPolicy.RETAIN,
         )
     ```