How to use the merlin.utils.get_yaml_var function in merlin

else:
                LOG.warning(
                    "The env:variables section does not have an OUTPUT_PATH"
                    "specified, multi-machine checks cannot be performed."
                )

        worker_args = get_yaml_var(worker_val, "args", celery_args)
        with suppress(KeyError):
            if worker_val["args"] is None:
                worker_args = ""

        worker_nodes = get_yaml_var(worker_val, "nodes", None)

        worker_batch = get_yaml_var(worker_val, "batch", None)

        wsteps = get_yaml_var(worker_val, "steps", steps)
        queues = spec.make_queue_string(wsteps).split(",")

        # Check for missing arguments
        parallel = batch_check_parallel(spec)
        if parallel:
            if "--concurrency" not in worker_args:
                LOG.warning(
                    "The worker arg --concurrency [1-4] is recommended "
                    "when running parallel tasks"
                )
            if "--prefetch-multiplier" not in worker_args:
                LOG.warning(
                    "The worker arg --prefetch-multiplier 1 is "
                    "recommended when running parallel tasks"
                )
            if "fair" not in worker_args:

f"The output path, {output_path}, is not accessible on this host, {hostname}"
                    )
            else:
                LOG.warning(
                    "The env:variables section does not have an OUTPUT_PATH"
                    "specified, multi-machine checks cannot be performed."
                )

        worker_args = get_yaml_var(worker_val, "args", celery_args)
        with suppress(KeyError):
            if worker_val["args"] is None:
                worker_args = ""

        worker_nodes = get_yaml_var(worker_val, "nodes", None)

        worker_batch = get_yaml_var(worker_val, "batch", None)

        wsteps = get_yaml_var(worker_val, "steps", steps)
        queues = spec.make_queue_string(wsteps).split(",")

        # Check for missing arguments
        parallel = batch_check_parallel(spec)
        if parallel:
            if "--concurrency" not in worker_args:
                LOG.warning(
                    "The worker arg --concurrency [1-4] is recommended "
                    "when running parallel tasks"
                )
            if "--prefetch-multiplier" not in worker_args:
                LOG.warning(
                    "The worker arg --prefetch-multiplier 1 is "
                    "recommended when running parallel tasks"

if launcher == "lsf":
            # The jsrun utility does not have a time argument
            launchs = f"jsrun -a 1 -c ALL_CPUS -g ALL_GPUS --bind=none -n {nodes}"

    launchs += f" {launch_args}"

    # Allow for any pre launch manipulation, e.g. module load
    # hwloc/1.11.10-cuda
    if launch_pre:
        launchs = f"{launch_pre} {launchs}"

    worker_cmd = f"{launchs} {com}"

    if btype == "flux":
        flux_path = get_yaml_var(batch, "flux_path", "")
        flux_opts = get_yaml_var(batch, "flux_start_opts", "")
        flux_exec_workers = get_yaml_var(batch, "flux_exec_workers", True)

        flux_exec = ""
        if flux_exec_workers:
            flux_exec = "flux exec"

        if "/" in flux_path:
            flux_path += "/"

        flux_exe = os.path.join(flux_path, "flux")

        launch = (
            f"{launchs} {flux_exe} start {flux_opts} {flux_exec} `which {shell}` -c"
        )
        worker_cmd = f'{launch} "{com}"'

return com

    if nodes is None:
        # Use the value in the batch section
        nodes = get_yaml_var(batch, "nodes", None)

    # Get the number of nodes from the environment if unset
    if nodes is None or nodes == "all":
        nodes = get_node_count(default=1)

    bank = get_yaml_var(batch, "bank", "")
    queue = get_yaml_var(batch, "queue", "")
    shell = get_yaml_var(batch, "shell", "bash")
    walltime = get_yaml_var(batch, "walltime", "")

    launch_pre = get_yaml_var(batch, "launch_pre", "")
    launch_args = get_yaml_var(batch, "launch_args", "")
    worker_launch = get_yaml_var(batch, "worker_launch", "")

    if btype == "flux":
        launcher = get_batch_type()
    else:
        launcher = get_batch_type()

    launchs = worker_launch
    if not launchs:
        if btype == "slurm" or launcher == "slurm":
            launchs = f"srun --mpi=none -N {nodes} -n {nodes}"
            if bank:
                launchs += f" -A {bank}"
            if queue:
                launchs += f" -p {queue}"

senv = spec.environment
    spenv = os.environ.copy()
    yenv = None
    if senv:
        yenv = get_yaml_var(senv, "variables", {})
        for k, v in yenv.items():
            spenv[str(k)] = str(v)
            # For expandvars
            os.environ[str(k)] = str(v)

    worker_list = []
    local_queues = []

    for worker_name, worker_val in workers.items():
        worker_machines = get_yaml_var(worker_val, "machines", None)
        if worker_machines:
            LOG.debug("check machines = ", check_machines(worker_machines))
            if not check_machines(worker_machines):
                continue

            if yenv:
                output_path = get_yaml_var(yenv, "OUTPUT_PATH", None)
                if output_path and not os.path.exists(output_path):
                    hostname = socket.gethostname()
                    LOG.error(
                        f"The output path, {output_path}, is not accessible on this host, {hostname}"
                    )
            else:
                LOG.warning(
                    "The env:variables section does not have an OUTPUT_PATH"
                    "specified, multi-machine checks cannot be performed."

spenv[str(k)] = str(v)
            # For expandvars
            os.environ[str(k)] = str(v)

    worker_list = []
    local_queues = []

    for worker_name, worker_val in workers.items():
        worker_machines = get_yaml_var(worker_val, "machines", None)
        if worker_machines:
            LOG.debug("check machines = ", check_machines(worker_machines))
            if not check_machines(worker_machines):
                continue

            if yenv:
                output_path = get_yaml_var(yenv, "OUTPUT_PATH", None)
                if output_path and not os.path.exists(output_path):
                    hostname = socket.gethostname()
                    LOG.error(
                        f"The output path, {output_path}, is not accessible on this host, {hostname}"
                    )
            else:
                LOG.warning(
                    "The env:variables section does not have an OUTPUT_PATH"
                    "specified, multi-machine checks cannot be performed."
                )

        worker_args = get_yaml_var(worker_val, "args", celery_args)
        with suppress(KeyError):
            if worker_val["args"] is None:
                worker_args = ""

launchs += f" -t {walltime}"
        if launcher == "lsf":
            # The jsrun utility does not have a time argument
            launchs = f"jsrun -a 1 -c ALL_CPUS -g ALL_GPUS --bind=none -n {nodes}"

    launchs += f" {launch_args}"

    # Allow for any pre launch manipulation, e.g. module load
    # hwloc/1.11.10-cuda
    if launch_pre:
        launchs = f"{launch_pre} {launchs}"

    worker_cmd = f"{launchs} {com}"

    if btype == "flux":
        flux_path = get_yaml_var(batch, "flux_path", "")
        flux_opts = get_yaml_var(batch, "flux_start_opts", "")
        flux_exec_workers = get_yaml_var(batch, "flux_exec_workers", True)

        flux_exec = ""
        if flux_exec_workers:
            flux_exec = "flux exec"

        if "/" in flux_path:
            flux_path += "/"

        flux_exe = os.path.join(flux_path, "flux")

        launch = (
            f"{launchs} {flux_exe} start {flux_opts} {flux_exec} `which {shell}` -c"
        )
        worker_cmd = f'{launch} "{com}"'

if nodes is None:
        # Use the value in the batch section
        nodes = get_yaml_var(batch, "nodes", None)

    # Get the number of nodes from the environment if unset
    if nodes is None or nodes == "all":
        nodes = get_node_count(default=1)

    bank = get_yaml_var(batch, "bank", "")
    queue = get_yaml_var(batch, "queue", "")
    shell = get_yaml_var(batch, "shell", "bash")
    walltime = get_yaml_var(batch, "walltime", "")

    launch_pre = get_yaml_var(batch, "launch_pre", "")
    launch_args = get_yaml_var(batch, "launch_args", "")
    worker_launch = get_yaml_var(batch, "worker_launch", "")

    if btype == "flux":
        launcher = get_batch_type()
    else:
        launcher = get_batch_type()

    launchs = worker_launch
    if not launchs:
        if btype == "slurm" or launcher == "slurm":
            launchs = f"srun --mpi=none -N {nodes} -n {nodes}"
            if bank:
                launchs += f" -A {bank}"
            if queue:
                launchs += f" -p {queue}"
            if walltime:

# all non flux lsf submissions need to be local.
    if btype == "local" or "lsf" in btype:
        return com

    if nodes is None:
        # Use the value in the batch section
        nodes = get_yaml_var(batch, "nodes", None)

    # Get the number of nodes from the environment if unset
    if nodes is None or nodes == "all":
        nodes = get_node_count(default=1)

    bank = get_yaml_var(batch, "bank", "")
    queue = get_yaml_var(batch, "queue", "")
    shell = get_yaml_var(batch, "shell", "bash")
    walltime = get_yaml_var(batch, "walltime", "")

    launch_pre = get_yaml_var(batch, "launch_pre", "")
    launch_args = get_yaml_var(batch, "launch_args", "")
    worker_launch = get_yaml_var(batch, "worker_launch", "")

    if btype == "flux":
        launcher = get_batch_type()
    else:
        launcher = get_batch_type()

    launchs = worker_launch
    if not launchs:
        if btype == "slurm" or launcher == "slurm":
            launchs = f"srun --mpi=none -N {nodes} -n {nodes}"
            if bank:
                launchs += f" -A {bank}"

# A jsrun submission cannot be run under a parent jsrun so
    # all non flux lsf submissions need to be local.
    if btype == "local" or "lsf" in btype:
        return com

    if nodes is None:
        # Use the value in the batch section
        nodes = get_yaml_var(batch, "nodes", None)

    # Get the number of nodes from the environment if unset
    if nodes is None or nodes == "all":
        nodes = get_node_count(default=1)

    bank = get_yaml_var(batch, "bank", "")
    queue = get_yaml_var(batch, "queue", "")
    shell = get_yaml_var(batch, "shell", "bash")
    walltime = get_yaml_var(batch, "walltime", "")

    launch_pre = get_yaml_var(batch, "launch_pre", "")
    launch_args = get_yaml_var(batch, "launch_args", "")
    worker_launch = get_yaml_var(batch, "worker_launch", "")

    if btype == "flux":
        launcher = get_batch_type()
    else:
        launcher = get_batch_type()

    launchs = worker_launch
    if not launchs:
        if btype == "slurm" or launcher == "slurm":
            launchs = f"srun --mpi=none -N {nodes} -n {nodes}"