Conversion Destination Manager

class ConversionDestinationManager:
    """Manages conversion tracking destinations for a merchant account."""

    def __init__(self, merchant_id: str):
        """Initialize the manager with a merchant account ID.

        Args:
            merchant_id: The merchant account identifier
        """
        pass

    def create_destination(self, display_name: str, currency_code: str, attribution_model: str) -> str:
        """Create a new conversion destination.

        Args:
            display_name: The display name for the destination
            currency_code: The currency code (e.g., "USD", "EUR")
            attribution_model: The attribution model to use

        Returns:
            The identifier of the created destination

        Raises:
            ValueError: If any parameter is invalid
        """
        pass

    def update_destination(self, destination_id: str, display_name: str = None, attribution_model: str = None) -> None:
        """Update an existing conversion destination.

        Args:
            destination_id: The identifier of the destination to update
            display_name: The new display name (optional)
            attribution_model: The new attribution model (optional)

        Raises:
            ValueError: If the destination does not exist or parameters are invalid
        """
        pass

    def get_destination(self, destination_id: str) -> dict:
        """Retrieve destination information.

        Args:
            destination_id: The identifier of the destination

        Returns:
            A dictionary containing destination details with keys:
            - 'destination_id': str
            - 'display_name': str
            - 'currency_code': str
            - 'attribution_model': str
            - 'state': str

        Raises:
            ValueError: If the destination does not exist
        """
        pass