
+-----+----+-----+
| cyl | am | mpg |
+=====+====+=====+
| 4        | 23  |
+-----+----+-----+
| 4   | 1  | 28  |
+-----+----+-----+
| 6        | 19  |
+-----+----+-----+
| 6   | 1  | 21  |
+-----+----+-----+
| 8        | 15  |
+-----+----+-----+
| 8   | 1  | 15  |
+-----+----+-----+ 
