Construct new empty rows using list repetition

Signed-off-by: Olivier Gayot <olivier.gayot@sigexec.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/cameltris/playfield.py b/cameltris/playfield.py
index d1f4e9d..2e432b2 100644
--- a/cameltris/playfield.py
+++ b/cameltris/playfield.py
@@ -1,6 +1,6 @@
 class PlayField:
     def __init__(self):
-        self.grid = [[None for _ in range(10)] for _ in range(20)]
+        self.grid = [[None] * 10 for _ in range(20)]
 
     def burn_rows(self) -> int:
         """ Burn rows that can be filled and return how many of them were burnt """
@@ -11,7 +11,7 @@ class PlayField:
                 rows_to_burn.append(row)
 
         for row in rows_to_burn:
-            self.grid.insert(0, [None for _ in range(10)])
+            self.grid.insert(0, [None] * 10)
             self.grid.remove(row)
 
         return len(rows_to_burn)