specify allowed types for bindings

Author: hallvictoria

articles/azure-functions/functions-bindings-cosmosdb-v2-output.md

@@ -705,6 +705,12 @@ By default, when you write to the output parameter in your function, a document
 > [!NOTE]  
 > When you specify the ID of an existing document, it gets overwritten by the new output document.
 
+::: zone pivot="programming-language-python" 
+
+The output function parameter must be defined as `func.Out[func.Document]`. Refer to the [output example](#example) for details.
+
+::: zone-end
+
 ::: zone pivot="programming-language-csharp"  
 
 The parameter type supported by the Cosmos DB output binding depends on the Functions runtime version, the extension package version, and the C# modality used.

articles/azure-functions/functions-bindings-event-grid-output.md

@@ -693,6 +693,9 @@ There are two options for outputting an Event Grid message from a function:
 - **Return value**: Set the `name` property in *function.json* to `$return`. With this configuration, the function's return value is persisted as an Event Grid message.
 - **Imperative**: Pass a value to the [set](/python/api/azure-functions/azure.functions.out#set-val--t-----none) method of the parameter declared as an [Out](/python/api/azure-functions/azure.functions.out) type. The value passed to `set` is persisted as an Event Grid message.
 
+
+The output function parameter must be defined as `func.Out[str]`, `func.Out[bytes]`, `func.Out[func.EventGridOutputEvent]`, or `func.Out[List[func.EventGridOutputEvent]]`. Refer to the [output example](#example) for details.
+
 ::: zone-end
 
 ## Connections

articles/azure-functions/functions-bindings-event-hubs-output.md

@@ -458,6 +458,8 @@ There are two options for outputting an Event Hubs message from a function:
 
 - **Imperative**: Pass a value to the [set](/python/api/azure-functions/azure.functions.out#set-val--t-----none) method of the parameter declared as an [Out](/python/api/azure-functions/azure.functions.out) type. The value passed to `set` is persisted as an Event Hubs message.
 
+The output function parameter must be defined as `func.Out[func.EventHubEvent]` or `func.Out[List[func.EventHubEvent]]`. Refer to the [output example](#example) for details.
+
 ::: zone-end
 
 [!INCLUDE [functions-event-hubs-connections](../../includes/functions-event-hubs-connections.md)]

articles/azure-functions/functions-bindings-service-bus-output.md

@@ -622,8 +622,9 @@ Access the output message by using `context.bindings.<name>` where `<name>` is t
 ::: zone pivot="programming-language-powershell"  
 Output to the Service Bus is available via the `Push-OutputBinding` cmdlet where you pass arguments that match the name designated by binding's name parameter in the *function.json* file.
 ::: zone-end   
-::: zone pivot="programming-language-python"  
-Use the [Azure Service Bus SDK](../service-bus-messaging/index.yml) rather than the built-in output binding.
+::: zone pivot="programming-language-python" 
+The output function parameter must be defined as `func.Out[str]` or `func.Out[bytes]`. Refer to the [output example](#example) for details. 
+Alternatively, you can use the [Azure Service Bus SDK](../service-bus-messaging/index.yml) rather than the built-in output binding.
 ::: zone-end  
 For a complete example, see [the examples section](#example).
 

articles/azure-functions/functions-bindings-storage-queue-output.md

@@ -594,6 +594,8 @@ There are two options for writing from your function to the configured queue:
 
 - **Imperative**: Pass a value to the [set](/python/api/azure-functions/azure.functions.out#set-val--t-----none) method of the parameter declared as an [Out](/python/api/azure-functions/azure.functions.out) type. The value passed to `set` is persisted as a Queue storage message.
 
+The output function parameter must be defined as `func.Out[func.QueueMessage]`, `func.Out[str]`, or `func.Out[bytes]`. Refer to the [output example](#example) for details.
+
 ::: zone-end  
 
 [!INCLUDE [functions-storage-queue-connections](../../includes/functions-storage-queue-connections.md)]