diff --git a/src/qibotn/backends/__init__.py b/src/qibotn/backends/__init__.py
index 11eaf02..1547a3d 100644
--- a/src/qibotn/backends/__init__.py
+++ b/src/qibotn/backends/__init__.py
@@ -47,4 +47,4 @@ class MetaBackend:
             except:
                 available = False
             available_backends[platform] = available
-        return available_backends
\ No newline at end of file
+        return available_backends
diff --git a/src/qibotn/backends/quimb.py b/src/qibotn/backends/quimb.py
index d55bbab..fdbb387 100644
--- a/src/qibotn/backends/quimb.py
+++ b/src/qibotn/backends/quimb.py
@@ -113,7 +113,10 @@ class QuimbBackend(QibotnBackend, NumpyBackend):
         )
 
         frequencies = Counter(circ_quimb.sample(nshots)) if nshots is not None else None
-        main_frequencies = {state: count for state, count in frequencies.most_common(self.n_most_frequent_states)}
+        main_frequencies = {
+            state: count
+            for state, count in frequencies.most_common(self.n_most_frequent_states)
+        }
         computational_states = [state for state in main_frequencies.keys()]
         amplitudes = {
             state: circ_quimb.amplitude(state) for state in computational_states