diff --git a/instagram_archiver/client.py b/instagram_archiver/client.py
index 593a118..4659d8f 100644
--- a/instagram_archiver/client.py
+++ b/instagram_archiver/client.py
@@ -60,6 +60,10 @@ class AuthenticationError(Exception):
     pass
 
 
+class CSRFTokenNotFound(AuthenticationError):
+    pass
+
+
 class InstagramClient:
     """The client."""
     def __init__(self,
@@ -118,8 +122,10 @@ def _setup_session(self,
         })
         r = self._get_rate_limited('https://www.instagram.com', return_json=False)
         m = list(re.finditer(r'{"csrf_token":"([^"]+)"', r.text))
-        assert len(m) == 1, m
-        self._session.headers.update({'x-csrftoken': m[0].group(1)})
+        try:
+            self._session.headers.update({'x-csrftoken': m[0].group(1)})
+        except IndexError as e:
+            raise CSRFTokenNotFound from e
 
     def _save_to_log(self, url: str) -> None:
         if self._no_log:
diff --git a/package.json b/package.json
index 0d77be2..99c5463 100644
--- a/package.json
+++ b/package.json
@@ -45,8 +45,8 @@
     "gen-manpage": "sphinx-build -T -E -b man -d docs/_build/doctrees -D language=en docs man",
     "mypy": "poetry run mypy .",
     "qa": "yarn mypy && yarn ruff && yarn check-spelling && yarn check-formatting",
-    "ruff": "poetry run ruff .",
-    "ruff:fix": "poetry run ruff --fix .",
+    "ruff": "poetry run ruff check .",
+    "ruff:fix": "poetry run ruff check --fix .",
     "test": "poetry run pytest"
   },
   "version": "0.0.1"
diff --git a/pyproject.toml b/pyproject.toml
index 35b4084..6e7b51c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -133,8 +133,13 @@ mock_use_standalone_module = true
 
 [tool.ruff]
 cache-dir = "~/.cache/ruff"
-extend-ignore = ["C408", "PTH123", "Q000", "Q001", "Q003", "T201", "TD002", "TD003", "TD004"]
 namespace-packages = ["docs", "tests"]
+line-length = 100
+target-version = "py311"
+unsafe-fixes = true
+
+[tool.ruff.lint]
+extend-ignore = ["C408", "PTH123", "Q000", "Q001", "Q003", "T201", "TD002", "TD003", "TD004"]
 extend-select = [
   "A",
   "ASYNC",
@@ -188,7 +193,7 @@ extend-select = [
   "PLR0133",
   "PLR0206",
   "PLR0402",
-  "PLR1701",
+  "SIM101",
   "PLR1711",
   "PLR1714",
   "PLR1722",
@@ -226,11 +231,8 @@ extend-select = [
   "UP",
   "YTT",
 ]
-line-length = 100
-target-version = "py311"
-unsafe-fixes = true
 
-[tool.ruff.flake8-quotes]
+[tool.ruff.lint.flake8-quotes]
 inline-quotes = "single"
 multiline-quotes = "single"
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 1b9859e..e3ea77b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -17,6 +17,6 @@ def pytest_internalerror(excinfo: pytest.ExceptionInfo[BaseException]) -> NoRetu
         raise excinfo.value
 
 
-@pytest.fixture()
+@pytest.fixture
 def runner() -> CliRunner:
     return CliRunner()