How to use the pyperf._cpu_utils.format_cpu_list function in pyperf

else:
            isolated = False
            cpus = parse_cpu_list(cpus)

        if set_cpu_affinity(cpus):
            if self.args.verbose:
                if isolated:
                    text = ("Pin process to isolated CPUs: %s"
                            % format_cpu_list(cpus))
                else:
                    text = ("Pin process to CPUs: %s"
                            % format_cpu_list(cpus))
                print(text)

            if isolated:
                self.args.affinity = format_cpu_list(cpus)
        else:
            if not isolated:
                print("ERROR: CPU affinity not available.", file=sys.stderr)
                print("Use Python 3.3 or newer, or install psutil dependency")
                sys.exit(1)
            elif not self.args.quiet:
                print("WARNING: unable to pin worker processes to "
                      "isolated CPUs, CPU affinity not available")
                print("Use Python 3.3 or newer, or install psutil dependency")

cpus = get_isolated_cpus()
            if not cpus:
                # no isolated CPUs or unable to get the isolated CPUs
                return
        else:
            isolated = False
            cpus = parse_cpu_list(cpus)

        if set_cpu_affinity(cpus):
            if self.args.verbose:
                if isolated:
                    text = ("Pin process to isolated CPUs: %s"
                            % format_cpu_list(cpus))
                else:
                    text = ("Pin process to CPUs: %s"
                            % format_cpu_list(cpus))
                print(text)

            if isolated:
                self.args.affinity = format_cpu_list(cpus)
        else:
            if not isolated:
                print("ERROR: CPU affinity not available.", file=sys.stderr)
                print("Use Python 3.3 or newer, or install psutil dependency")
                sys.exit(1)
            elif not self.args.quiet:
                print("WARNING: unable to pin worker processes to "
                      "isolated CPUs, CPU affinity not available")
                print("Use Python 3.3 or newer, or install psutil dependency")

def collect_cpu_affinity(metadata, cpu_affinity, cpu_count):
    if not cpu_affinity:
        return
    if not cpu_count:
        return

    # CPU affinity
    if set(cpu_affinity) == set(range(cpu_count)):
        return

    metadata['cpu_affinity'] = format_cpu_list(cpu_affinity)

affinity = self.read_irqs_affinity()
        modified = []
        for irq in self.get_irqs():
            if self.permission_error:
                break

            cpus = affinity.get(irq)
            if new_cpus == cpus:
                continue

            if self.write_irq(irq, new_cpus):
                modified.append(irq)

        if modified:
            self.log_action("Set affinity of IRQ %s to CPU %s"
                            % (format_cpu_list(modified), format_cpu_list(new_cpus)))

def check_isolcpus(self):
        isolated = get_isolated_cpus()
        if isolated:
            self.log_state('Isolated CPUs (%s/%s): %s'
                           % (len(isolated), self.ncpu,
                              format_cpu_list(isolated)))
        elif self.ncpu > 1:
            self.log_state('No CPU is isolated')
            self.advice('Use isolcpus= kernel parameter '
                        'to isolate CPUs')

def write_default(self, new_affinity):
        default_smp_affinity = self.read_default_affinity()
        if new_affinity == default_smp_affinity:
            return

        mask = format_cpus_as_mask(new_affinity)
        try:
            write_text(self.default_affinity_path, mask)
        except IOError as exc:
            self.check_permission_error(exc)
            self.error("Failed to write %r into %s: %s"
                       % (mask, self.default_affinity_path, exc))
        else:
            self.log_action("Set default affinity to CPU %s"
                            % format_cpu_list(new_affinity))