Controllers are generated with unused variable

After starting `generate` I receive an error in generated controllers.
The error is

`generate` function is same as `test1` in [tests](https://github.com/devexperts/swagger-codegen-ts/blob/master/test/index.ts)

Libs:
```
"fp-ts": "^2.4.4",
"io-ts": "^2.0.1",
"io-ts-reporters": "^1.0.0",
"io-ts-types": "^0.5.2",
"@devexperts/swagger-codegen-ts": "^2.0.0-alpha.17",
"@devexperts/utils": "^1.0.0-alpha.11",
```

System: win10

Also, I checked tests here and got the same result.

STR:
- clone project
- yarn install
- yarn test:run