added is_empty method, cleaned Game repr

chess.py

@@ -39,11 +39,12 @@ class Game:
         for rank in ranks:
             r += rank + " |"
             for file in files:
-                piece = self.board[file+rank]
-                if piece.piece == None:
+                sq = file+rank
+                r += " "
+                if self.is_empty(sq):
                     r += " "
                 else:
-                    r += " " + repr(piece)
+                    r += repr(self.board[sq])
             r += "\n"
         r += "  +" + "-"*16 + "\n"
         r += " "*4 + " ".join(list(files))
@@ -61,6 +62,10 @@ class Game:
         for sq in cross(files, "78"):
             self.board[sq].color = "black"
 
+    def is_empty(self, sq):
+        return self.board[sq].piece == None
+
+
 
 
 def test():