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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 config_file_paths(self):
 r"""Get a list of config file paths. The list is built taking into account of the OS, priority and location. * custom path: /path/to/glances * Linux, SunOS: ~/.config/glances, /etc/glances * *BSD: ~/.config/glances, /usr/local/etc/glances * macOS: ~/Library/Application Support/glances, /usr/local/etc/glances * Windows: %APPDATA%\glances The config file will be searched in the following order of priority: * /path/to/file (via -C flag) * user's home directory (per-user settings) * system-wide directory (system-wide settings) """

        paths = []

        if self.config_dir:
            paths.append(self.config_dir)

        paths.append(os.path.join(user_config_dir(), self.config_filename))
        paths.append(os.path.join(system_config_dir(), self.config_filename))

        return paths