dengxiao01

### Checklist - [ ] I searched the [documentation](https://cobrapy.readthedocs.io). - [ ] I looked through [similar issues on GitHub](https://github.com/opencobra/cobrapy/issues). - [ ] I looked up "How to do ... in...

#### Problem description   #### Code Sample Create a [minimal, complete, verifiable example](https://stackoverflow.com/help/mcve). ```python ``` ``` ``` ### Context ``` ```