feat: update lead and lag functions to handle default_value as an array

Author: kosiew

python/datafusion/functions.py

@@ -2449,8 +2449,8 @@ def lead(
         partition_by: Expressions to partition the window frame on.
         order_by: Set ordering within the window frame.
     """
-    if not isinstance(default_value, pa.Scalar) and default_value is not None:
-        default_value = pa.scalar(default_value)
+    if default_value is not None and not hasattr(default_value, "__arrow_c_array__"):
+        default_value = pa.array([default_value])
 
     partition_by_raw = expr_list_to_raw_expr_list(partition_by)
     order_by_raw = sort_list_to_raw_sort_list(order_by)
@@ -2499,8 +2499,8 @@ def lag(
         partition_by: Expressions to partition the window frame on.
         order_by: Set ordering within the window frame.
     """
-    if not isinstance(default_value, pa.Scalar):
-        default_value = pa.scalar(default_value)
+    if default_value is not None and not hasattr(default_value, "__arrow_c_array__"):
+        default_value = pa.array([default_value])
 
     partition_by_raw = expr_list_to_raw_expr_list(partition_by)
     order_by_raw = sort_list_to_raw_sort_list(order_by)