fix: preserve complex objects in unwrap_py_scalar, only convert enums…

… to strings

Co-Authored-By: Myles Scolnick <myles@marimo.io>

marimo/_utils/narwhals_utils.py

@@ -141,8 +141,8 @@ def unwrap_narwhals_dataframe(df: Any) -> Any:
 def unwrap_py_scalar(value: Any) -> Any:
     """
     Convert a narwhals value to a python scalar if possible, otherwise return
-    the value as is. Datetime objects and primitive types are preserved.
-    Enums and other complex types are converted to strings.
+    the value as is. Datetime objects, primitive types, and complex objects like
+    dictionaries are preserved. Only enum/categorical types are converted to strings.
     """
     from datetime import datetime, date
     import polars as pl
@@ -160,14 +160,13 @@ def unwrap_py_scalar(value: Any) -> Any:
         # Check if the result is already a datetime/date after conversion
         if isinstance(scalar, (datetime, date)):
             return scalar
-        # For other primitive types
+        # For primitive types
         if isinstance(scalar, (str, int, float, bool, type(None))):
             return scalar
-        # For non-primitive types (including enums), convert to string
-        return str(scalar)
+        # For enums, convert to string, otherwise preserve the object
+        if hasattr(scalar, '__members__'):  # Check if it's an enum
+            return str(scalar)
+        return scalar
     except ValueError:
-        # If conversion fails, preserve primitives and datetimes
-        if isinstance(value, (str, int, float, bool, type(None), datetime, date)):
-            return value
-        # Convert other types to string
-        return str(value)
+        # If conversion fails, preserve the value as-is
+        return value