---

This section details on the original issue you should resolve

<issue_title>TypeScript errors when using methodNameBuilder (private type 'IROperationObject' / 'Operation')</issue_title>
<issue_description>### Description

After updating to the latest version, TypeScript shows errors when using methodNameBuilder.

Default export of the module has or is using private name 'IROperationObject'.ts
Default export of the module has or is using private name 'Operation'.

Reproducible example or configuration

import { defineConfig } from '@hey-api/openapi-ts';
import { isNil } from 'lodash';

export default defineConfig({
  input: 'http://localhost:5000/api/docs-json',
  output: './lib',
  parser: {
    transforms: {
      enums: false,
    },
  },
  plugins: [
    {
      name: '@hey-api/client-fetch',
      throwOnError: true,
      baseUrl: false,
      bundle: true,
    },
    {
      name: '@hey-api/transformers',
      dates: true,
    },
    {
      name: '@hey-api/sdk',
      transformer: true,
      asClass: true,
      classNameBuilder: (name: string) => `${name}Service`,
      methodNameBuilder: (operation) => {
        if ('operationId' in operation && !isNil(operation.operationId)) {
          const parts = operation.operationId!.split('_');

          if (parts.length === 1) {
            return parts[0];
          }

          return parts[1];
        }

        if ('id' in operation && !isNil(operation.id)) {
          return operation.id!;
        }

        return operation.path ?? '';
      },
    },
    {
      name: '@hey-api/typescript',
      enums: 'typescript',
    },
  ],
});

OpenAPI specification (optional)

No response

System information (optional)

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

@mrlubos @ArtemAstakhov can you share your tsconfig?