Solgraph throws an error "Error: Unexpected statement type (ExpressionStatement) in analyzed nodes." when running through klin-finance

`solgraph ./src/contracts/StakingContract.sol > diagram.png`

```
C:\Users\milaa\AppData\Roaming\npm\node_modules\solgraph\dist\index.js:106
          throw new Error(msg);
```

https://github.com/kilnfi/staking-contracts