# Buggy code
def _normalize_parameters(self, parameters):
    """Normalize a parameter list.
    Get the standard form of a parameter list, which includes:
        1. Use long options to replace short options
        2. Remove the unrecognized parameters
        3. Sort the result parameter list
    An example: ['-g', '-n'] ==> ['--name', '--resource-group']
    """

    from knack.deprecation import Deprecated

    normalized_parameters = []
    try:
        cmd_table = self.cli_ctx.invocation.commands_loader.command_table.get(
            self.command, None
        )
        parameter_table = cmd_table.arguments if cmd_table else None
    except AttributeError:
        parameter_table = None

    if parameters:
        rules = {
            "-h": "--help",
            "-o": "--output",
            "--only-show-errors": None,
            "--help": None,
            "--output": None,
            "--query": None,
            "--debug": None,
            "--verbose": None,
        }

        if parameter_table:
            for argument in parameter_table.values():
                options = argument.type.settings["options_list"]
                options = (
                    option for option in options if not isinstance(option, Deprecated)
                )
                try:
                    sorted_options = sorted(options, key=len, reverse=True)
                    standard_form = sorted_options[0]

                    for option in sorted_options[1:]:
                        rules[option] = standard_form
                    rules[standard_form] = None
                except TypeError:
                    logger.debug(
                        "Unexpected argument options `%s` of type `%s`.",
                        options,
                        type(options).__name__,
                    )

        for parameter in parameters:
            if parameter in rules:
                normalized_form = rules.get(parameter, None) or parameter
                normalized_parameters.append(normalized_form)
            else:
                logger.debug(
                    '"%s" is an invalid parameter for command "%s".',
                    parameter,
                    self.command,
                )

    return sorted(normalized_parameters)


# Traceback (IndexError)
list index out of range
Traceback (most recent call last):
python3.9/site-packages/knack/cli.py, ln 215, in invoke
cmd_result = self.invocation.execute(args)
cli/core/commands/__init__.py, ln 579, in execute
parsed_args = self.parser.parse_args(args)
python3.9/site-packages/knack/parser.py, ln 262, in parse_args
return super(CLICommandParser, self).parse_args(args)
3.9/lib/python3.9/argparse.py, ln 1818, in parse_args
args, argv = self.parse_known_args(args, namespace)
...
azure/cli/core/command_recommender.py, ln 162, in recommend_a_command
normalized_parameters = self._normalize_parameters(parameters)
azure/cli/core/command_recommender.py, ln 244, in _normalize_parameters
standard_form = sorted_options[0]
IndexError: list index out of range

# Fixed code
def _normalize_parameters(self, parameters):
    """Normalize a parameter list.
    Get the standard form of a parameter list, which includes:
        1. Use long options to replace short options
        2. Remove the unrecognized parameters
        3. Sort the result parameter list
    An example: ['-g', '-n'] ==> ['--name', '--resource-group']
    """

    from knack.deprecation import Deprecated

    normalized_parameters = []
    try:
        cmd_table = self.cli_ctx.invocation.commands_loader.command_table.get(
            self.command, None
        )
        parameter_table = cmd_table.arguments if cmd_table else None
    except AttributeError:
        parameter_table = None

    if parameters:
        rules = {
            "-h": "--help",
            "-o": "--output",
            "--only-show-errors": None,
            "--help": None,
            "--output": None,
            "--query": None,
            "--debug": None,
            "--verbose": None,
        }

        if parameter_table:
            for argument in parameter_table.values():
                options = argument.type.settings["options_list"]
                options = [
                    option for option in options if not isinstance(option, Deprecated)
                ]
                # skip the positional arguments
                if not options:
                    continue
                try:
                    sorted_options = sorted(options, key=len, reverse=True)
                    standard_form = sorted_options[0]

                    for option in sorted_options[1:]:
                        rules[option] = standard_form
                    rules[standard_form] = None
                except TypeError:
                    logger.debug(
                        "Unexpected argument options `%s` of type `%s`.",
                        options,
                        type(options).__name__,
                    )

        for parameter in parameters:
            if parameter in rules:
                normalized_form = rules.get(parameter, None) or parameter
                normalized_parameters.append(normalized_form)
            else:
                logger.debug(
                    '"%s" is an invalid parameter for command "%s".',
                    parameter,
                    self.command,
                )

    return sorted(normalized_parameters)