def write_default_config(self, overwrite=False):
        """Write the default config to the user's config file.

        :param bool overwrite: Write over an existing config if it exists.
        """
        destination = self.user_config_file()
        if not overwrite and os.path.exists(destination):
            return

        with io.open(destination, mode='wb') as f:
            self.default_config.write(f)
Write the default config to the user's config file.

        :param bool overwrite: Write over an existing config if it exists.