How to use the coverage.backward.iitems function in coverage

def test_iitems(self):
        d = {'a': 1, 'b': 2, 'c': 3}
        items = [('a', 1), ('b', 2), ('c', 3)]
        self.assertCountEqual(list(iitems(d)), items)

def write_pickled_file(self, covdata, filename):
        """Write coverage data as pickled `filename`."""
        # Create the file data.
        file_data = {}

        if covdata._arcs:
            file_data['arcs'] = dict((f, list(amap)) for f, amap in iitems(covdata._arcs))
        else:
            file_data['lines'] = dict((f, list(lmap)) for f, lmap in iitems(covdata._lines))

        # Write the pickle to the file.
        with open(filename, 'wb') as file_obj:
            pickle.dump(file_data, file_obj, 2)

any_set = False
        try:
            for option_spec in self.CONFIG_FILE_OPTIONS:
                was_set = self._set_attr_from_config_option(cp, *option_spec)
                if was_set:
                    any_set = True
        except ValueError as err:
            raise CoverageException("Couldn't read config file %s: %s" % (filename, err))

        # Check that there are no unrecognized options.
        all_options = collections.defaultdict(set)
        for option_spec in self.CONFIG_FILE_OPTIONS:
            section, option = option_spec[1].split(":")
            all_options[section].add(option)

        for section, options in iitems(all_options):
            real_section = cp.has_section(section)
            if real_section:
                for unknown in set(cp.options(section)) - options:
                    raise CoverageException(
                        "Unrecognized option '[%s] %s=' in config file %s" % (
                            real_section, unknown, filename
                        )
                    )

        # [paths] is special
        if cp.has_section('paths'):
            for option in cp.options('paths'):
                self.paths[option] = cp.getlist('paths', option)
                any_set = True

        # plugins can have options

def add_file_tracers(self, file_tracers):
        """Add per-file plugin information.

        `file_tracers` is { filename: plugin_name, ... }

        """
        if self._debug.should('dataop'):
            self._debug.write("Adding file tracers: %d files" % (len(file_tracers),))
        if not file_tracers:
            return
        self._start_using()
        with self._connect() as con:
            for filename, plugin_name in iitems(file_tracers):
                file_id = self._file_id(filename)
                if file_id is None:
                    raise CoverageException(
                        "Can't add file tracer data for unmeasured file '%s'" % (filename,)
                    )

                existing_plugin = self.file_tracer(filename)
                if existing_plugin:
                    if existing_plugin != plugin_name:
                        raise CoverageException(
                            "Conflicting file tracer name for '%s': %r vs %r" % (
                                filename, existing_plugin, plugin_name,
                            )
                        )
                elif plugin_name:
                    con.execute(

if self.config._config_contents
                else '-none-'
            ),
            ('data_file', self._data.data_filename() if self._data is not None else "-none-"),
            ('python', sys.version.replace('\n', '')),
            ('platform', platform.platform()),
            ('implementation', platform.python_implementation()),
            ('executable', sys.executable),
            ('def_encoding', sys.getdefaultencoding()),
            ('fs_encoding', sys.getfilesystemencoding()),
            ('pid', os.getpid()),
            ('cwd', os.getcwd()),
            ('path', sys.path),
            ('environment', sorted(
                ("%s = %s" % (k, v))
                for k, v in iitems(os.environ)
                if any(slug in k for slug in ("COV", "PY"))
            )),
            ('command_line', " ".join(getattr(sys, 'argv', ['-none-']))),
            ]

        if self._inorout:
            info.extend(self._inorout.sys_info())

        info.extend(CoverageData.sys_info())

        return info

def write(self):
        """Write the current status."""
        status_file = os.path.join(self.directory, self.STATUS_FILE)
        files = {}
        for filename, fileinfo in iitems(self.files):
            fileinfo['index']['nums'] = fileinfo['index']['nums'].init_args()
            files[filename] = fileinfo

        status = {
            'format': self.STATUS_FORMAT,
            'version': coverage.__version__,
            'globals': self.globals,
            'files': files,
        }
        with open(status_file, "w") as fout:
            json.dump(status, fout, separators=(',', ':'))

def from_args(self, **kwargs):
        """Read config values from `kwargs`."""
        for k, v in iitems(kwargs):
            if v is not None:
                if k in self.MUST_BE_LIST and isinstance(v, string_class):
                    v = [v]
                setattr(self, k, v)

def _branch_lines(self):
        """Returns a list of line numbers that have more than one exit."""
        return [l1 for l1,count in iitems(self.exit_counts) if count > 1]

def missing_formatted(self, branches=False):
        """The missing line numbers, formatted nicely.

        Returns a string like "1-2, 5-11, 13-14".

        If `branches` is true, includes the missing branch arcs also.

        """
        if branches and self.has_arcs():
            arcs = iitems(self.missing_branch_arcs())
        else:
            arcs = None

        return format_lines(self.statements, self.missing, arcs=arcs)