def get_option(self, option_name: str) -> TConfigValueOut | None:
        """Get an option from the configuration.

        `option_name` is a colon-separated string indicating the section and
        option name.  For example, the ``branch`` option in the ``[run]``
        section of the config file would be indicated with `"run:branch"`.

        Returns the value of the option.

        """
        # Special-cased options.
        if option_name == "paths":
            return self.paths

        # Check all the hard-coded options.
        for option_spec in self.CONFIG_FILE_OPTIONS:
            attr, where = option_spec[:2]
            if where == option_name:
                return getattr(self, attr)  # type: ignore[no-any-return]

        # See if it's a plugin option.
        plugin_name, _, key = option_name.partition(":")
        if key and plugin_name in self.plugins:
            return self.plugin_options.get(plugin_name, {}).get(key)

        # If we get here, we didn't find the option.
        raise ConfigError(f"No such option: {option_name!r}")
Get an option from the configuration.

        `option_name` is a colon-separated string indicating the section and
        option name.  For example, the ``branch`` option in the ``[run]``
        section of the config file would be indicated with `"run:branch"`.

        Returns the value of the option.

        
coverage/config.py