diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5eea484..30c0590 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,6 +33,8 @@ jobs:
         run: uv pip install -e ".[dev]"
       - name: Run ruff
         run: uv run ruff check .
+      - name: Run ruff format check
+        run: uv run ruff format --check .
       - name: Run mypy
         run: uv run mypy jsoncsv
 
diff --git a/README.md b/README.md
index 5d4d005..f2ca629 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,7 @@ Just use them.
 
 ## Requirements
 
-- Python 3.8 or higher
+- Python 3.11 or higher
 
 ## Quick Start
 
diff --git a/jsoncsv/dumptool.py b/jsoncsv/dumptool.py
index 7ce0d98..6bfe2ce 100644
--- a/jsoncsv/dumptool.py
+++ b/jsoncsv/dumptool.py
@@ -67,8 +67,8 @@ def load_headers(
 class DumpExcel(Dump, ReadHeadersMixin):
     def initialize(self, **kwargs: Any) -> None:
         super().initialize(**kwargs)
-        self._read_row = kwargs.get('read_row')
-        self._sort_type = kwargs.get('sort_type')
+        self._read_row = kwargs.get("read_row")
+        self._sort_type = kwargs.get("sort_type")
 
     def prepare(self) -> None:
         headers, datas = self.load_headers(self.fin, self._read_row, self._sort_type)
@@ -104,10 +104,7 @@ def write_headers(self) -> None:
         self.csv_writer.writeheader()
 
     def write_obj(self, obj: dict[str, JsonType]) -> None:
-        patched_obj: dict[str, str] = {
-            key: self.patch_value(value)
-            for key, value in obj.items()
-        }
+        patched_obj: dict[str, str] = {key: self.patch_value(value) for key, value in obj.items()}
         assert self.csv_writer is not None
         self.csv_writer.writerow(patched_obj)
 
@@ -121,8 +118,8 @@ class DumpXLS(DumpExcel):
     def initialize(self, **kwargs: Any) -> None:
         super().initialize(**kwargs)
 
-        self.sheet = kwargs.get('sheet', 'Sheet1')
-        self.wb = xlwt.Workbook(encoding='utf-8')
+        self.sheet = kwargs.get("sheet", "Sheet1")
+        self.wb = xlwt.Workbook(encoding="utf-8")
         self.ws = self.wb.add_sheet(self.sheet)
         self.row = 0
         self.cloumn = 0
diff --git a/jsoncsv/jsontool.py b/jsoncsv/jsontool.py
index 3d99636..09efcc3 100644
--- a/jsoncsv/jsontool.py
+++ b/jsoncsv/jsontool.py
@@ -19,9 +19,9 @@
 )
 
 __all__ = [
-    'convert_json',
-    'expand',
-    'restore',
+    "convert_json",
+    "expand",
+    "restore",
 ]
 
 # Type alias for the func parameter in convert_json
@@ -90,7 +90,7 @@ def from_leaf(leafs: Iterable[LeafInputType]) -> JsonType:
     return dict(child)  # type: ignore[arg-type]
 
 
-def expand(origin: JsonType, separator: str = '.', safe: bool = False) -> dict[str, JsonType]:
+def expand(origin: JsonType, separator: str = ".", safe: bool = False) -> dict[str, JsonType]:
     root = origin
     leafs = gen_leaf(root)
 
@@ -105,7 +105,7 @@ def expand(origin: JsonType, separator: str = '.', safe: bool = False) -> dict[s
     return expobj
 
 
-def restore(expobj: dict[str, JsonType], separator: str = '.', safe: bool = False) -> JsonType:
+def restore(expobj: dict[str, JsonType], separator: str = ".", safe: bool = False) -> JsonType:
     leafs: list[tuple[DecodedPathType, JsonType]] = []
 
     items = expobj.items()
@@ -113,7 +113,7 @@ def restore(expobj: dict[str, JsonType], separator: str = '.', safe: bool = Fals
     for key, value in items:
         path: DecodedPathType = decode_safe_key(key, separator) if safe else key.split(separator)
 
-        if key == '':
+        if key == "":
             path = []
 
         leafs.append((path, value))
@@ -126,13 +126,13 @@ def convert_json(
     fin: io.TextIOBase,
     fout: io.TextIOBase,
     func: ConvertFunc,
-    separator: str = '.',
+    separator: str = ".",
     safe: bool = False,
     json_array: bool = False,
 ) -> None:
-    '''
+    """
     ensure fin/fout is TextIO
-    '''
+    """
 
     if func not in [expand, restore]:
         raise ValueError("unknow convert_json type")
@@ -158,4 +158,4 @@ def gen_objs_from_array() -> Iterator[JsonType]:
         new = func(obj, separator=separator, safe=safe)
         content = json.dumps(new, ensure_ascii=False)
         fout.write(content)
-        fout.write('\n')
+        fout.write("\n")
diff --git a/jsoncsv/main.py b/jsoncsv/main.py
index 16c22fa..11ee365 100644
--- a/jsoncsv/main.py
+++ b/jsoncsv/main.py
@@ -15,40 +15,22 @@
 
 def separator_type(sep: str) -> str:
     if len(sep) != 1:
-        raise click.BadOptionUsage(option_name='separator',
-                                   message='separator can only be a char')
+        raise click.BadOptionUsage(option_name="separator", message="separator can only be a char")
     if sep == unit_char:
-        raise click.BadOptionUsage(option_name='separator',
-                                   message='separator can not be `\\` ')
+        raise click.BadOptionUsage(option_name="separator", message="separator can not be `\\` ")
     return sep
 
 
 @click.command()
-@click.option('-A',
-              '--array',
-              'json_array',
-              is_flag=True,
-              default=False,
-              help='read input file as json array')
-@click.option('-s',
-              '--sep',
-              'separator',
-              type=separator_type,
-              default='.',
-              help='separator')
-@click.option('--safe', is_flag=True, help='use safe mode')
-@click.option('-r',
-              '--restore',
-              'restore',
-              is_flag=True,
-              help='restore expanded json')
-@click.option('-e',
-              '--expand',
-              'expand',
-              is_flag=True,
-              help='expand json (default True)')
-@click.argument('input', type=click.File('r', encoding='utf-8'), default='-')
-@click.argument('output', type=click.File('w', encoding='utf-8'), default='-')
+@click.option(
+    "-A", "--array", "json_array", is_flag=True, default=False, help="read input file as json array"
+)
+@click.option("-s", "--sep", "separator", type=separator_type, default=".", help="separator")
+@click.option("--safe", is_flag=True, help="use safe mode")
+@click.option("-r", "--restore", "restore", is_flag=True, help="restore expanded json")
+@click.option("-e", "--expand", "expand", is_flag=True, help="expand json (default True)")
+@click.argument("input", type=click.File("r", encoding="utf-8"), default="-")
+@click.argument("output", type=click.File("w", encoding="utf-8"), default="-")
 def jsoncsv(
     output: io.TextIOBase,
     input: io.TextIOBase,
@@ -59,42 +41,34 @@ def jsoncsv(
     json_array: bool,
 ) -> None:
     if expand and restore:
-        raise click.UsageError('can not choose both, default is `-e`')
+        raise click.UsageError("can not choose both, default is `-e`")
 
     func: Callable[..., Any]
     func = expand_fn if not restore else restore_fn
 
-    convert_json(input,
-                 output,
-                 func,
-                 separator=separator,
-                 safe=safe,
-                 json_array=json_array)
+    convert_json(input, output, func, separator=separator, safe=safe, json_array=json_array)
 
     input.close()
     output.close()
 
 
 @click.command()
-@click.option('-t',
-              '--type',
-              'type_',
-              type=click.Choice(['csv', 'xls']),
-              default='csv',
-              help='choose dump format')
-@click.option('-r',
-              '--row',
-              type=int,
-              default=None,
-              help='number of pre-read `row` lines to load `headers`')
-@click.option('-s',
-              '--sort',
-              'sort_',
-              is_flag=True,
-              default=False,
-              help='enable sort the headers keys')
-@click.argument('input', type=click.File('r', encoding='utf-8'), default='-')
-@click.argument('output', type=click.Path(), default='-')
+@click.option(
+    "-t",
+    "--type",
+    "type_",
+    type=click.Choice(["csv", "xls"]),
+    default="csv",
+    help="choose dump format",
+)
+@click.option(
+    "-r", "--row", type=int, default=None, help="number of pre-read `row` lines to load `headers`"
+)
+@click.option(
+    "-s", "--sort", "sort_", is_flag=True, default=False, help="enable sort the headers keys"
+)
+@click.argument("input", type=click.File("r", encoding="utf-8"), default="-")
+@click.argument("output", type=click.Path(), default="-")
 def mkexcel(
     output: str,
     input: io.TextIOBase,
@@ -107,13 +81,13 @@ def mkexcel(
         klass = dumptool.DumpXLS
 
     # Open file in appropriate mode based on type
-    if output == '-':
-        fout: Any = sys.stdout.buffer if type_ == 'xls' else sys.stdout
+    if output == "-":
+        fout: Any = sys.stdout.buffer if type_ == "xls" else sys.stdout
         dump_excel(input, fout, klass, read_row=row, sort_type=sort_)
     else:
-        mode = 'wb' if type_ == 'xls' else 'w'
-        encoding = None if type_ == 'xls' else 'utf-8'
-        newline = '' if type_ == 'csv' else None
+        mode = "wb" if type_ == "xls" else "w"
+        encoding = None if type_ == "xls" else "utf-8"
+        newline = "" if type_ == "csv" else None
         with open(output, mode, encoding=encoding, newline=newline) as fout:
             dump_excel(input, fout, klass, read_row=row, sort_type=sort_)
 
diff --git a/jsoncsv/utils.py b/jsoncsv/utils.py
index 68fa200..8af33f6 100644
--- a/jsoncsv/utils.py
+++ b/jsoncsv/utils.py
@@ -2,14 +2,14 @@
 # 2016.11.20
 
 # Type aliases for JSON data structures
-JsonType = dict[str, 'JsonType'] | list['JsonType'] | str | int | float | bool | None
+JsonType = dict[str, "JsonType"] | list["JsonType"] | str | int | float | bool | None
 PathType = list[int | str]  # Can contain ints (array indices) or strings (dict keys)
 DecodedPathType = list[str]  # Decoded paths from keys are always strings
 LeafType = tuple[PathType, JsonType]
 # Type for leafs that can contain either PathType (from gen_leaf) or DecodedPathType (from restore)
 LeafInputType = LeafType | tuple[DecodedPathType, JsonType]
 
-unit_char = '\\'
+unit_char = "\\"
 
 
 def encode_safe_key(path: list[str], separator: str) -> str:
@@ -20,13 +20,13 @@ def encode_safe_key(path: list[str], separator: str) -> str:
 
 def decode_safe_key(key: str, separator: str) -> list[str]:
     path: list[str] = []
-    p = ''
+    p = ""
     escape = False
 
     for char in key:
         if escape and char == separator:
             path.append(p)
-            p = ''
+            p = ""
             escape = False
         elif escape and char == unit_char:
             p += unit_char
@@ -36,6 +36,6 @@ def decode_safe_key(key: str, separator: str) -> list[str]:
         else:
             p += char
 
-    if p != '':
+    if p != "":
         path.append(p)
     return path
diff --git a/tests/test_dumptool.py b/tests/test_dumptool.py
index a92cf09..e8c8961 100644
--- a/tests/test_dumptool.py
+++ b/tests/test_dumptool.py
@@ -7,39 +7,54 @@
 
 
 class TestDumpTool(unittest.TestCase):
-
     # FIXME (使用虚拟文件)
     def test_dumpexcel_csv(self):
-        with open('./fixture/files/expand.1.json', encoding='utf-8') as fin, \
-                open('./fixture/files/tmp.output.1.csv', 'w', encoding='utf-8', newline='') as fout:
+        with (
+            open("./fixture/files/expand.1.json", encoding="utf-8") as fin,
+            open("./fixture/files/tmp.output.1.csv", "w", encoding="utf-8", newline="") as fout,
+        ):
             dump_excel(fin, fout, DumpCSV)
 
-        with open('./fixture/files/output.1.csv', encoding='utf-8') as output, \
-                open('./fixture/files/tmp.output.1.csv', encoding='utf-8') as fout:
+        with (
+            open("./fixture/files/output.1.csv", encoding="utf-8") as output,
+            open("./fixture/files/tmp.output.1.csv", encoding="utf-8") as fout,
+        ):
             self.assertEqual(output.read(), fout.read())
 
     def test_dumpexcel_csv_with_sort(self):
-        with open('./fixture/files/expand.1.json', encoding='utf-8') as fin, \
-                open('./fixture/files/tmp.output.1.sort.csv', 'w', encoding='utf-8', newline='') as fout:
+        with (
+            open("./fixture/files/expand.1.json", encoding="utf-8") as fin,
+            open(
+                "./fixture/files/tmp.output.1.sort.csv", "w", encoding="utf-8", newline=""
+            ) as fout,
+        ):
             dump_excel(fin, fout, DumpCSV, sort_type=True)
 
-        with open('./fixture/files/output.1.sort.csv', encoding='utf-8') as output, \
-                open('./fixture/files/tmp.output.1.sort.csv', encoding='utf-8') as fout:
+        with (
+            open("./fixture/files/output.1.sort.csv", encoding="utf-8") as output,
+            open("./fixture/files/tmp.output.1.sort.csv", encoding="utf-8") as fout,
+        ):
             self.assertEqual(output.read(), fout.read())
 
     def test_dumpcexcel_xls(self):
-        with open('./fixture/files/expand.1.json', encoding='utf-8') as fin, \
-                open('./fixture/files/tmp.output.1.xls', 'wb') as fout:
+        with (
+            open("./fixture/files/expand.1.json", encoding="utf-8") as fin,
+            open("./fixture/files/tmp.output.1.xls", "wb") as fout,
+        ):
             dump_excel(fin, fout, DumpXLS)
 
     def test_dump_csv_with_non_ascii(self):
-        with open('./fixture/files/expand.2.json', encoding='utf-8') as fin, \
-                open('./fixture/files/tmp.output.2.csv', 'w', encoding='utf-8', newline='') as fout:
+        with (
+            open("./fixture/files/expand.2.json", encoding="utf-8") as fin,
+            open("./fixture/files/tmp.output.2.csv", "w", encoding="utf-8", newline="") as fout,
+        ):
             dump_excel(fin, fout, DumpCSV)
 
     def test_dump_xls_with_non_ascii(self):
-        with open('./fixture/files/expand.2.json', encoding='utf-8') as fin, \
-                open('./fixture/files/tmp.output.2.xls', 'wb') as fout:
+        with (
+            open("./fixture/files/expand.2.json", encoding="utf-8") as fin,
+            open("./fixture/files/tmp.output.2.xls", "wb") as fout,
+        ):
             dump_excel(fin, fout, DumpXLS)
 
     def test_dump_xls_with_dict(self):
diff --git a/tests/test_escape.py b/tests/test_escape.py
index 5e3d7e7..dd9f963 100644
--- a/tests/test_escape.py
+++ b/tests/test_escape.py
@@ -7,29 +7,28 @@
 
 
 class Testescape(unittest.TestCase):
-
     def test_all(self):
-        path = ['A', 'B', '..', '\\.\\ww']
+        path = ["A", "B", "..", "\\.\\ww"]
 
-        for sep in 'AB.w':
+        for sep in "AB.w":
             key = encode_safe_key(path, sep)
             _path = decode_safe_key(key, sep)
 
         self.assertListEqual(path, _path)
 
     def test_encode(self):
-        path = ['A', 'B', 'C', 'www.xxx.com']
-        sep = '.'
+        path = ["A", "B", "C", "www.xxx.com"]
+        sep = "."
         key = encode_safe_key(path, sep)
 
-        self.assertEqual(key, 'A\\.B\\.C\\.www.xxx.com')
+        self.assertEqual(key, "A\\.B\\.C\\.www.xxx.com")
 
     def test_decode(self):
-        key = 'A\\.B\\.C\\.www.xxx.com'
-        sep = '.'
+        key = "A\\.B\\.C\\.www.xxx.com"
+        sep = "."
         path = decode_safe_key(key, sep)
 
-        self.assertEqual(path[0], 'A')
-        self.assertEqual(path[1], 'B')
-        self.assertEqual(path[2], 'C')
-        self.assertEqual(path[3], 'www.xxx.com')
+        self.assertEqual(path[0], "A")
+        self.assertEqual(path[1], "B")
+        self.assertEqual(path[2], "C")
+        self.assertEqual(path[3], "www.xxx.com")
diff --git a/tests/test_jsoncsv.py b/tests/test_jsoncsv.py
index 4637b92..7cf82c0 100644
--- a/tests/test_jsoncsv.py
+++ b/tests/test_jsoncsv.py
@@ -11,54 +11,50 @@
 class Testjsoncsv(unittest.TestCase):
     def test_jsoncsv_expand(self):
         runner = CliRunner()
-        args = ['-e', 'fixture/files/raw.0.json',
-                'fixture/files/tmp.expand.0.json']
+        args = ["-e", "fixture/files/raw.0.json", "fixture/files/tmp.expand.0.json"]
         result = runner.invoke(jsoncsv, args=args)
         assert result.exit_code == 0
 
     def test_jsoncsv_expand_with_json_array(self):
         runner = CliRunner()
-        args = ['-e', 'fixture/files/raw.1.json',
-                'fixture/files/tmp.expand.1.json', '-A']
+        args = ["-e", "fixture/files/raw.1.json", "fixture/files/tmp.expand.1.json", "-A"]
         result = runner.invoke(jsoncsv, args=args)
         assert result.exit_code == 0
 
     def test_jsoncsv_expand_restore(self):
         runner = CliRunner(echo_stdin=True)
-        result = runner.invoke(jsoncsv,
-                               args=['-e', 'fixture/files/raw.2.json',
-                                     'fixture/files/tmp.expand.2.json'])
+        result = runner.invoke(
+            jsoncsv, args=["-e", "fixture/files/raw.2.json", "fixture/files/tmp.expand.2.json"]
+        )
         assert result.exit_code == 0
-        result = runner.invoke(jsoncsv,
-                               args=['-r', 'fixture/files/tmp.expand.2.json',
-                                     'fixture/files/tmp.restore.2.json'])
+        result = runner.invoke(
+            jsoncsv,
+            args=["-r", "fixture/files/tmp.expand.2.json", "fixture/files/tmp.restore.2.json"],
+        )
         assert result.exit_code == 0
 
-        with open('fixture/files/raw.2.json') as f:
+        with open("fixture/files/raw.2.json") as f:
             input_data = [json.loads(line) for line in f]
 
-        with open('fixture/files/tmp.restore.2.json') as f:
+        with open("fixture/files/tmp.restore.2.json") as f:
             resotre_data = [json.loads(line) for line in f]
 
         self.assertEqual(input_data, resotre_data)
 
     def test_jsoncsv_with_error_args(self):
         runner = CliRunner()
-        args = ['-s', 'aa', '-e', 'fixture/files/raw.0.json',
-                'fixture/files/tmp.expand.0.json']
+        args = ["-s", "aa", "-e", "fixture/files/raw.0.json", "fixture/files/tmp.expand.0.json"]
         result = runner.invoke(jsoncsv, args=args)
         assert result.exit_code != 0
 
     def test_jsoncsv_with_error_sep_args(self):
         runner = CliRunner()
-        args = ['-s', '\\', '-e', 'fixture/files/raw.0.json',
-                'fixture/files/tmp.expand.0.json']
+        args = ["-s", "\\", "-e", "fixture/files/raw.0.json", "fixture/files/tmp.expand.0.json"]
         result = runner.invoke(jsoncsv, args=args)
         assert result.exit_code != 0
 
     def test_jsoncsv_with_error_args_expand_and_restore(self):
         runner = CliRunner()
-        args = ['-r', '-e', 'fixture/files/raw.0.json',
-                'fixture/files/tmp.expand.0.json']
+        args = ["-r", "-e", "fixture/files/raw.0.json", "fixture/files/tmp.expand.0.json"]
         result = runner.invoke(jsoncsv, args=args)
         assert result.exit_code != 0
diff --git a/tests/test_jsontool.py b/tests/test_jsontool.py
index 39b16ab..141d3da 100644
--- a/tests/test_jsontool.py
+++ b/tests/test_jsontool.py
@@ -8,7 +8,6 @@
 
 
 class TestJSONTool(unittest.TestCase):
-
     def test_string(self):
         s = "sss"
         exp = expand(s)
@@ -28,9 +27,7 @@ def test_dict(self):
             "w": 5,
             "t": {
                 "m": 0,
-                "x": {
-                    "y": "z"
-                },
+                "x": {"y": "z"},
             },
         }
 
@@ -40,13 +37,7 @@ def test_dict(self):
         self.assertDictEqual(s, _s)
 
     def test_complex(self):
-        s = [
-            {"s": 0},
-            {"t": ["2", {"x": "z"}]},
-            0,
-            "w",
-            ["x", "g", 1]
-        ]
+        s = [{"s": 0}, {"t": ["2", {"x": "z"}]}, 0, "w", ["x", "g", 1]]
         exp = expand(s)
         _s = restore(exp)
 
@@ -60,16 +51,16 @@ def test_complex(self):
 
     def test_is_array_index(self):
         self.assertTrue(is_array_index([0, 1, 2, 3]))
-        self.assertTrue(is_array_index(['0', '1', '2', '3']))
+        self.assertTrue(is_array_index(["0", "1", "2", "3"]))
         # string order
-        self.assertTrue(is_array_index(['0', '1', '10', '2', '3', '4', '5', '6', '7', '8', '9']))
+        self.assertTrue(is_array_index(["0", "1", "10", "2", "3", "4", "5", "6", "7", "8", "9"]))
         self.assertFalse(is_array_index([1, 2, 3]))
-        self.assertFalse(is_array_index(['0', 1, 2]))
+        self.assertFalse(is_array_index(["0", 1, 2]))
 
     def test_unicode(self):
         data = [
             {"河流名字": "长江", "河流长度": "6000千米"},
-            {"河流名字": "黄河", "河流长度": "5000千米"}
+            {"河流名字": "黄河", "河流长度": "5000千米"},
         ]
 
         expobj = expand(data)
@@ -81,8 +72,8 @@ def test_expand_with_safe(self):
             "api.a.com": {"qps": 100, "p95": 20, "p99": 100},
         }
         expobj = expand(data, safe=True)
-        self.assertEqual(expobj['api.a.com\\.p95'], 20)
-        self.assertEqual(expobj['api.a.com\\.p99'], 100)
+        self.assertEqual(expobj["api.a.com\\.p95"], 20)
+        self.assertEqual(expobj["api.a.com\\.p99"], 100)
 
         origin = restore(expobj, safe=True)
         self.assertEqual(origin, data)
@@ -98,7 +89,6 @@ def test_expand_and_restore(self):
 
 
 class TestConvertJSON(unittest.TestCase):
-
     def test_convert_expand(self):
         fin = io.StringIO('{"a":{"b":3}}\n{"a":{"c":4}}\n')
         fout = io.StringIO()
diff --git a/tests/test_mkexcel.py b/tests/test_mkexcel.py
index 61b0646..78e6b9d 100644
--- a/tests/test_mkexcel.py
+++ b/tests/test_mkexcel.py
@@ -11,21 +11,18 @@
 class Testmkexcel(unittest.TestCase):
     def test_mkexcel_csv(self):
         runner = CliRunner()
-        args = ['fixture/files/expand.0.json',
-                'fixture/files/tmp.expand.0.csv']
+        args = ["fixture/files/expand.0.json", "fixture/files/tmp.expand.0.csv"]
         result = runner.invoke(mkexcel, args=args)
         assert result.exit_code == 0
 
     def test_mkexcel_xls(self):
         runner = CliRunner()
-        args = ['-t', 'xls', 'fixture/files/expand.0.json',
-                'fixture/files/tmp.expand.0.xls']
+        args = ["-t", "xls", "fixture/files/expand.0.json", "fixture/files/tmp.expand.0.xls"]
         result = runner.invoke(mkexcel, args=args)
         assert result.exit_code == 0
 
     def test_mkexcel_with_error(self):
         runner = CliRunner()
-        args = ['-t', 'xlsx', 'fixture/files/expand.0.json',
-                'fixture/files/tmp.expand.0.xls']
+        args = ["-t", "xlsx", "fixture/files/expand.0.json", "fixture/files/tmp.expand.0.xls"]
         result = runner.invoke(mkexcel, args=args)
         assert result.exit_code == 2