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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _help_preprocess(self, help, cmdname):
 """Hook to preprocess a help string before writing to stdout. "help" is the help string to process. "cmdname" is the canonical sub-command name for which help is being given, or None if the help is not specific to a command. By default the following template variables are interpolated in help content. (Note: these are similar to Python 2.4's string.Template interpolation but not quite.) ${name} The tool's/shell's name, i.e. 'self.name'. ${option_list} A formatted table of options for this shell/tool. ${command_list} A formatted table of available sub-commands. ${help_list} A formatted table of additional help topics (i.e. 'help_*' methods with no matching 'do_*' method). ${cmd_name} The name (and aliases) for this sub-command formatted as: ${cmd_usage} A formatted usage block inferred from the command function signature. ${cmd_option_list} A formatted table of options for this sub-command. (This is only available for commands using the optparse integration, i.e. using @cmdln.option decorators or manually setting the 'optparser' attribute on the 'do_*' method.) Returns the processed help. """

        preprocessors = {
            "${name}": self._help_preprocess_name,
            "${option_list}": self._help_preprocess_option_list,
            "${command_list}": self._help_preprocess_command_list,
            "${help_list}": self._help_preprocess_help_list,
            "${cmd_name}": self._help_preprocess_cmd_name,
            "${cmd_usage}": self._help_preprocess_cmd_usage,
            "${cmd_option_list}": self._help_preprocess_cmd_option_list,
        }

        for marker, preprocessor in preprocessors.items():
            if marker in help:
                help = preprocessor(help, cmdname)
        return help