langchain/utilities/powerbi.py/PowerBIDataset/token_or_credential_present
class PowerBIDataset:    def token_or_credential_present(cls, values: Dict[str, Any]) -> Dict[str, Any]:
        """Validate that at least one of token and credentials is present."""
        if "token" in values or "credential" in values:
            return values
        raise ValueError("Please provide either a credential or a token.")