Issue number: #5589

Summary

Changes

This Pull Request addresses an issue with the PydanticSerializer when used in conjunction with the idempotent_function decorator. Currently, the serializer does not support optional return types (Optional[T] or T | None), leading to errors when functions are designed to return None.

Example

@idempotent_function(
    data_keyword_argument="order",
    config=config,
    persistence_store=dynamodb,
    output_serializer=PydanticSerializer(model=OrderOutput),
)
def process_order(order: Order) -> OrderOutput | None:
    if order:
        return OrderOutput(order_id=order.order_id)
    return None

Changes made to fix

• Type Handling: Modify the type-checking logic in the PydanticSerializer to recognize and accept optional return types.
• Error Messaging: Implement clear error messages that guide users on supported return types if an invalid type is encountered.
• Documentation: Updates the documentation to include information about optional return types.

User experience

Customers can now use None as return type.

Checklist

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• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Acknowledgment

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