[opt_transport] Execution Issue - Missing Variable

The following error is being reported

```
---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[10], line 1
----> 1 for i in range(len(sol_found)):
      2     print(f"运输方案 {i}
: ", sol_found[i])
      3     print(f"     最小成本 {i}
: ", cost[i])

NameError: name 'sol_found' is not defined
```

