diff --git a/python/pyspark/sql/conversion.py b/python/pyspark/sql/conversion.py
index 9110a63827253..745680ad0b713 100644
--- a/python/pyspark/sql/conversion.py
+++ b/python/pyspark/sql/conversion.py
@@ -891,8 +891,8 @@ def convert_other(value: Any) -> Any:
                 return value
 
             return convert_other
-        else:  # pragma: no cover
-            assert False, f"Need converter for {dataType} but failed to find one."
+
+        assert False, f"_need_converter returned True for {dataType} but no converter was created."
 
     @staticmethod
     def convert(data: Sequence[Any], schema: StructType, use_large_var_types: bool) -> "pa.Table":