How to use the mobly.utils.cli_cmd_to_string function in mobly

raw_name: string, the raw unsanitized name of the adb command to
                format.
            args: string or list of strings, arguments to the adb command.
                See subprocess.Proc() documentation.
            shell: bool, True to run this command through the system shell,
                False to invoke it directly. See subprocess.Proc() docs.

        Returns:
            The adb command in a format appropriate for subprocess. If shell is
                True, then this is a string; otherwise, this is a list of
                strings.
        """
        args = args or ''
        name = raw_name.replace('_', '-')
        if shell:
            args = utils.cli_cmd_to_string(args)
            # Add quotes around "adb" in case the ADB path contains spaces. This
            # is pretty common on Windows (e.g. Program Files).
            if self.serial:
                adb_cmd = '"%s" -s "%s" %s %s' % (ADB, self.serial, name, args)
            else:
                adb_cmd = '"%s" %s %s' % (ADB, name, args)
        else:
            adb_cmd = [ADB]
            if self.serial:
                adb_cmd.extend(['-s', self.serial])
            adb_cmd.append(name)
            if args:
                if isinstance(args, basestring):
                    adb_cmd.append(args)
                else:
                    adb_cmd.extend(args)

"""
        if timeout and timeout <= 0:
            raise ValueError('Timeout is not a positive value: %s' % timeout)
        try:
            (ret, out, err) = utils.run_command(args,
                                                shell=shell,
                                                timeout=timeout)
        except psutil.TimeoutExpired:
            raise AdbTimeoutError(cmd=args,
                                  timeout=timeout,
                                  serial=self.serial)

        if stderr:
            stderr.write(err)
        logging.debug('cmd: %s, stdout: %s, stderr: %s, ret: %s',
                      utils.cli_cmd_to_string(args), out, err, ret)
        if ret == 0:
            return out
        else:
            raise AdbError(cmd=args,
                           stdout=out,
                           stderr=err,
                           ret_code=ret,
                           serial=self.serial)

def __str__(self):
        return 'Timed out executing command "%s" after %ss.' % (
            utils.cli_cmd_to_string(self.cmd), self.timeout)

line = proc.stdout.readline()
                if line:
                    handler(line)
                else:
                    break
        finally:
            # Note, communicate will not contain any buffered output.
            (unexpected_out, err) = proc.communicate()
            if unexpected_out:
                out = '[unexpected stdout] %s' % unexpected_out
                for line in unexpected_out.splitlines():
                    handler(line)

        ret = proc.returncode
        logging.debug('cmd: %s, stdout: %s, stderr: %s, ret: %s',
                      utils.cli_cmd_to_string(args), out, err, ret)
        if ret == 0:
            return err
        else:
            raise AdbError(cmd=args, stdout=out, stderr=err, ret_code=ret)