fix: correct typo in null_treatment parameter documentation

Author: kosiew

python/datafusion/functions.py

@@ -1524,9 +1524,7 @@ def cardinality(array: Expr) -> Expr:
 
 
 def empty(array: Expr) -> Expr:
-    """
-    This is an alias for :py:func:`array_empty`.
-    """
+    """This is an alias for :py:func:`array_empty`."""
     return array_empty(array)
 
 
@@ -2148,7 +2146,7 @@ def first_value(
         expression: Argument to perform bitwise calculation on
         filter: If provided, only compute against rows for which the filter is True
         order_by: Set the ordering of the expression to evaluate
-        null_treatment: Assign whether to respect or ignull null values.
+        null_treatment: Assign whether to respect or ignore null values.
     """
     order_by_raw = sort_list_to_raw_sort_list(order_by)
     filter_raw = filter.expr if filter is not None else None
@@ -2180,7 +2178,7 @@ def last_value(
         expression: Argument to perform bitwise calculation on
         filter: If provided, only compute against rows for which the filter is True
         order_by: Set the ordering of the expression to evaluate
-        null_treatment: Assign whether to respect or ignull null values.
+        null_treatment: Assign whether to respect or ignore null values.
     """
     order_by_raw = sort_list_to_raw_sort_list(order_by)
     filter_raw = filter.expr if filter is not None else None
@@ -2214,7 +2212,7 @@ def nth_value(
         n: Index of value to return. Starts at 1.
         filter: If provided, only compute against rows for which the filter is True
         order_by: Set the ordering of the expression to evaluate
-        null_treatment: Assign whether to respect or ignull null values.
+        null_treatment: Assign whether to respect or ignore null values.
     """
     order_by_raw = sort_list_to_raw_sort_list(order_by)
     filter_raw = filter.expr if filter is not None else None