diff --git a/pandas/core/dtypes/cast.py b/pandas/core/dtypes/cast.py
index fa1d5097971a3..d53478bc309b7 100644
--- a/pandas/core/dtypes/cast.py
+++ b/pandas/core/dtypes/cast.py
@@ -1133,7 +1133,11 @@ def convert_dtypes(
                 base_dtype = np.dtype(str)
             else:
                 base_dtype = inferred_dtype
-            if base_dtype.kind == "O" and len(input_array) > 0 and isna(input_array).all():
+            if (
+                base_dtype.kind == "O"
+                and len(input_array) > 0
+                and isna(input_array).all()
+            ):
                 import pyarrow as pa
 
                 pa_type = pa.null()