def generate_sbi_json(num_pbs: int = 3, project: str = 'sip',
                      programme_block: str = 'sip_demos',
                      pb_config: Union[dict, List[dict]] = None,
                      workflow_config:
                      Union[dict, List[dict]] = None,
                      register_workflows=True) -> str:
    """Return a JSON string used to configure an SBI."""
    return json.dumps(generate_sbi_config(num_pbs, project, programme_block,
                                          pb_config,
                                          workflow_config, register_workflows))