Parses a single config file, populating ‘sections’ to look like:
- {‘DEFAULT’: {‘key’: [value, ...], ...},
- ...}
Also populates self._normalized which looks the same but with normalized section names.
A ConfigParser which handles multi-opts.
All methods in this class which accept config names should treat a section name of None as ‘DEFAULT’.
This class was deprecated in Mitaka and should be removed in Ocata. _Namespace holds values, ConfigParser._parse_file reads one file into a _Namespace and ConfigOpts._parse_config_files reads multiple files into a _Namespace.