def METHOD_NAME(schema, is_prop=False):
    from ._arg import AAZSimpleTypeArg, AAZCompoundTypeArg
    short_summary = schema._help.get("short-summary", "")
    if isinstance(schema, AAZSimpleTypeArg) and schema.enum:
        choices = schema.enum.to_choices()
        if choices:
            if short_summary:
                short_summary += '  '
            short_summary += 'Allowed values: {}.'.format(', '.join(sorted([str(x) for x in choices])))
    elif isinstance(schema, AAZCompoundTypeArg):
        if is_prop:
            if short_summary:
                short_summary += '  '
            short_summary += shorthand_help_messages['show-help']
    return short_summary