在数据框中，列具有以下输入：
| id| priority| status| datetime|data_as_of_Date|Amount|open_close|
| 1|Unassigned| Fixed| 10/8/2019 0:00| 2/12/2020 0:00| 40| Closed|
| 1|Unassigned| New|2/12/2019 11:00| 2/12/2020 0:00| 20| Open|
| 1|Unassigned|Fix in progress|9/12/2019 11:00| 2/12/2020 0:00| 90| Open|
| 3| Critical| Removed|5/17/2019 12:00| 2/12/2020 0:00| 33| Closed|
| 3|Unassigned|Fix in progress|5/26/2019 10:00| 2/12/2020 0:00| 30| Open|
| 3| Critical| New| 5/8/2019 3:00| 2/12/2020 0:00| 34| Open|
| 3|Unassigned| Fixed| 7/29/2019 7:00| 2/12/2020 0:00| 29| Closed|
Calculate the count how many times the open_close column got changed per company?
