diff --git a/xlsxwriter/worksheet.py b/xlsxwriter/worksheet.py
index 31453c77b..3725ef51d 100644
--- a/xlsxwriter/worksheet.py
+++ b/xlsxwriter/worksheet.py
@@ -2987,11 +2987,12 @@ def conditional_format(
                 options["formula"] = "FLOOR(%s,1)=TODAY()+1" % start_cell
 
             elif options["criteria"] == "last7Days":
-                options[
-                    "formula"
-                ] = "AND(TODAY()-FLOOR(%s,1)<=6,FLOOR(%s,1)<=TODAY())" % (
-                    start_cell,
-                    start_cell,
+                options["formula"] = (
+                    "AND(TODAY()-FLOOR(%s,1)<=6,FLOOR(%s,1)<=TODAY())"
+                    % (
+                        start_cell,
+                        start_cell,
+                    )
                 )
 
             elif options["criteria"] == "lastWeek":
@@ -3023,11 +3024,12 @@ def conditional_format(
                 )
 
             elif options["criteria"] == "thisMonth":
-                options[
-                    "formula"
-                ] = "AND(MONTH(%s)=MONTH(TODAY()),YEAR(%s)=YEAR(TODAY()))" % (
-                    start_cell,
-                    start_cell,
+                options["formula"] = (
+                    "AND(MONTH(%s)=MONTH(TODAY()),YEAR(%s)=YEAR(TODAY()))"
+                    % (
+                        start_cell,
+                        start_cell,
+                    )
                 )
 
             elif options["criteria"] == "nextMonth":