How to use the apio.util.exec_command function in apio

def _run_command(self, command, silent=False):
        result = {}
        system_base_dir = util.get_package_dir('tools-system')
        system_bin_dir = util.safe_join(system_base_dir, 'bin')

        on_stdout = None if silent else self._on_stdout
        on_stderr = self._on_stderr

        if util.check_package(
            self.name,
            self.version,
            self.spec_version,
            system_bin_dir
        ):
            result = util.exec_command(
                util.safe_join(system_bin_dir, command + self.ext),
                stdout=util.AsyncPipe(on_stdout),
                stderr=util.AsyncPipe(on_stderr))

        return result

def _ftdi_disable_windows(self):
        click.secho('Launch device manager')
        click.secho(FTDI_UNINSTALL_DRIVER_INSTRUCTIONS, fg='yellow')

        result = util.exec_command('mmc devmgmt.msc')
        return result.get('returncode')

command == 'upload' or \
           command == 'time':
            if board:
                processing_board = board
            else:
                processing_board = 'custom board'
            click.echo('[%s] Processing %s' % (
                datetime.datetime.now().strftime('%c'),
                click.style(processing_board, fg='cyan', bold=True)))
            click.secho('-' * terminal_width, bold=True)

        if self.profile.get_verbose_mode() > 0:
            click.secho('Executing: {}'.format(
                ' '.join(util.scons_command + ['-Q', command] + variables)))

        result = util.exec_command(
            util.scons_command + ['-Q', command] + variables,
            stdout=util.AsyncPipe(self._on_stdout),
            stderr=util.AsyncPipe(self._on_stderr)
        )

        # -- Print result
        exit_code = result.get('returncode')
        is_error = exit_code != 0
        summary_text = ' Took %.2f seconds ' % (time.time() - start_time)
        half_line = '=' * int(
            ((terminal_width - len(summary_text) - 10) / 2))
        click.echo('%s [%s]%s%s' % (
            half_line,
            (click.style(' ERROR ', fg='red', bold=True)
             if is_error else click.style('SUCCESS', fg='green', bold=True)),
            summary_text,

def _serial_disable_windows(self):
        click.secho('Launch device manager')
        click.secho(SERIAL_UNINSTALL_DRIVER_INSTRUCTIONS, fg='yellow')

        result = util.exec_command('mmc devmgmt.msc')
        return result.get('returncode')

def _serial_enable_windows(self):
        drivers_base_dir = util.get_package_dir('tools-drivers')
        drivers_bin_dir = util.safe_join(drivers_base_dir, 'bin')

        try:
            if util.check_package(
                self.name,
                self.version,
                self.spec_version,
                drivers_bin_dir
            ):
                click.secho('Launch drivers configuration tool')
                click.secho(SERIAL_INSTALL_DRIVER_INSTRUCTIONS, fg='yellow')
                result = util.exec_command(
                    util.safe_join(drivers_bin_dir, 'serial_install.exe'))
                click.secho('Serial drivers configuration finished',
                            fg='green')
            else:
                result = 1
        except Exception as e:
            click.secho('Error: ' + str(e), fg='red')
            result = 1

        if not isinstance(result, int):
            result = result.get('returncode')
        return result