[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

src/coffea/nanoevents/mapping/uproot.py

@@ -149,9 +149,7 @@ def _extract_base_form(cls, tree, iteritems_options={}):
                 continue
             if isinstance(branch, uproot.behaviors.RNTuple.HasFields):
                 form = branch.to_akform()
-                form = json.loads(
-                    form.to_json()
-                )
+                form = json.loads(form.to_json())
                 branch_forms[key] = form
                 continue
             if "," in key or "!" in key: