model.as_pyscipopt() error!

[yigeNNU]

Describe the bug

scip_model = env.model.as_pyscipopt()
File "src/pyscipopt/scip.pyx", line 992, in pyscipopt.scip.Model.from_ptr
TypeError: an integer is required

Setting

• OS: LInux
• Python version: 3.9.7
• Ecole version: ecole_tree_mdp

I have printed the 'env.model', follows:
<class 'ecole.core.scip.Model'>
But, it still has the above bug. Please help me, thanks!