How to use the httpie.cli.requestitems.RequestItems.from_args function in httpie

def test_multiple_text_fields_with_same_field_name(self):
        items = RequestItems.from_args(
            request_item_args=[
                self.key_value_arg('text_field=a'),
                self.key_value_arg('text_field=b')
            ],
            as_form=True,
        )
        assert items.data['text_field'] == ['a', 'b']
        assert list(items.data.items()) == [
            ('text_field', 'a'),
            ('text_field', 'b'),
        ]

def test_escape_longsep(self):
        items = RequestItems.from_args([
            self.key_value_arg(r'bob\:==foo'),
        ])
        assert items.params == {
            'bob:': 'foo'
        }

def test_multiple_file_fields_with_same_field_name(self):
        items = RequestItems.from_args([
            self.key_value_arg('file_field@' + FILE_PATH_ARG),
            self.key_value_arg('file_field@' + FILE_PATH_ARG),
        ])
        assert len(items.files['file_field']) == 2

def test_escape_separator(self):
        items = RequestItems.from_args([
            # headers
            self.key_value_arg(r'foo\:bar:baz'),
            self.key_value_arg(r'jack\@jill:hill'),

            # data
            self.key_value_arg(r'baz\=bar=foo'),

            # files
            self.key_value_arg(r'bar\@baz@%s' % FILE_PATH_ARG),
        ])
        # `requests.structures.CaseInsensitiveDict` => `dict`
        headers = dict(items.headers._store.values())

        assert headers == {
            'foo:bar': 'baz',
            'jack@jill': 'hill',

def test_valid_items(self):
        items = RequestItems.from_args([
            self.key_value_arg('string=value'),
            self.key_value_arg('Header:value'),
            self.key_value_arg('Unset-Header:'),
            self.key_value_arg('Empty-Header;'),
            self.key_value_arg('list:=["a", 1, {}, false]'),
            self.key_value_arg('obj:={"a": "b"}'),
            self.key_value_arg('ed='),
            self.key_value_arg('bool:=true'),
            self.key_value_arg('file@' + FILE_PATH_ARG),
            self.key_value_arg('query==value'),
            self.key_value_arg('string-embed=@' + FILE_PATH_ARG),
            self.key_value_arg('raw-json-embed:=@' + JSON_FILE_PATH_ARG),
        ])

        # Parsed headers
        # `requests.structures.CaseInsensitiveDict` => `dict`

def _parse_items(self):
        """
        Parse `args.request_items` into `args.headers`, `args.data`,
        `args.params`, and `args.files`.

        """
        try:
            request_items = RequestItems.from_args(
                request_item_args=self.args.request_items,
                as_form=self.args.form,
            )
        except ParseError as e:
            if self.args.traceback:
                raise
            self.error(e.args[0])
        else:
            self.args.headers = request_items.headers
            self.args.data = request_items.data
            self.args.files = request_items.files
            self.args.params = request_items.params

        if self.args.files and not self.args.form:
            # `http url @/path/to/file`
            file_fields = list(self.args.files.keys())