planet subscriptions cancel prints null
**Expected behavior**
```
planet-client-python$> planet subscriptions cancel c3195b51-518d-42dc-ad5e-b2ff127070b4
```
has no output

**Actual behavior (describe the problem)**
`planet subscriptions cancel` prints null
```
planet-client-python$> planet subscriptions cancel c3195b51-518d-42dc-ad5e-b2ff127070b4
null
```

diff --git a/planet/cli/subscriptions.py b/planet/cli/subscriptions.py
index bb466a4..901a729 100644
--- a/planet/cli/subscriptions.py
+++ b/planet/cli/subscriptions.py
@@ -96,8 +96,7 @@ async def cancel_subscription_cmd(ctx, subscription_id, pretty):
     """Cancels a subscription and prints the API response."""
     async with CliSession() as session:
         client = SubscriptionsClient(session)
-        sub = await client.cancel_subscription(subscription_id)
-        echo_json(sub, pretty)
+        _ = await client.cancel_subscription(subscription_id)
 
 
 @subscriptions.command(name='update')
['planet/cli/subscriptions.py']