diff --git a/repo2docker/contentproviders/dataverse.py b/repo2docker/contentproviders/dataverse.py
index 3cf8cb20..e786fe24 100644
--- a/repo2docker/contentproviders/dataverse.py
+++ b/repo2docker/contentproviders/dataverse.py
@@ -99,7 +99,7 @@ def parse_dataverse_url(self, url: str) -> Tuple[str, bool]:
 
         Raises a ValueError if we can not parse the url
         """
-        parsed_url= urlparse(url)
+        parsed_url = urlparse(url)
         path = parsed_url.path
         qs = parse_qs(parsed_url.query)
         base_url = f"{parsed_url.scheme}://{parsed_url.netloc}"
@@ -157,10 +157,10 @@ def get_datafiles(self, url: str) -> List[dict]:
         resp = self._request(dataset_api_url, headers={"accept": "application/json"})
         if resp.status_code == 404 and is_ambiguous:
             # It's possible this is a *file* persistent_id, not a dataset one
-            persistent_id = self.get_dataset_id_from_file_id(
-                base_url, persistent_id
+            persistent_id = self.get_dataset_id_from_file_id(base_url, persistent_id)
+            dataset_api_url = (
+                f"{base_url}/api/datasets/:persistentId?persistentId={persistent_id}"
             )
-            dataset_api_url = f"{base_url}/api/datasets/:persistentId?persistentId={persistent_id}"
             resp = self._request(
                 dataset_api_url, headers={"accept": "application/json"}
             )
@@ -181,7 +181,7 @@ def fetch(self, spec, output_dir, yield_output=False):
         url = spec
         parsed_url = urlparse(url)
         # FIXME: Support determining API URL better
-        base_url = f'{parsed_url.scheme}://{parsed_url.netloc}'
+        base_url = f"{parsed_url.scheme}://{parsed_url.netloc}"
 
         yield f"Fetching Dataverse record {url}.\n"
 
diff --git a/tests/contentproviders/test_dataverse.py b/tests/contentproviders/test_dataverse.py
index 7b6d1f60..9ca25852 100644
--- a/tests/contentproviders/test_dataverse.py
+++ b/tests/contentproviders/test_dataverse.py
@@ -6,6 +6,7 @@
 
 from repo2docker.contentproviders import Dataverse
 
+
 @pytest.mark.parametrize(
     ("doi", "resolved"),
     [
@@ -45,22 +46,22 @@ def test_detect(doi, resolved):
         (
             "https://dataverse.harvard.edu/file.xhtml?persistentId=doi:10.7910/DVN/6ZXAGT/3YRRYJ",
             "doi:10.7910/DVN/6ZXAGT",
-            False
+            False,
         ),
         (
             "https://dataverse.harvard.edu/citation?persistentId=doi:10.7910/DVN/TJCLKP",
             "doi:10.7910/DVN/TJCLKP",
-            True
+            True,
         ),
         (
             "https://dataverse.harvard.edu/api/access/datafile/3323458",
             "doi:10.7910/DVN/3MJ7IR",
-            False
+            False,
         ),
         (
             "https://data.cimmyt.org/dataset.xhtml?persistentId=hdl:11529/10016",
             "hdl:11529/10016",
-            False
+            False,
         ),
     ],
 )