Invalid C# code produced in latest version (11.15.4.0) if path definition has an underscore

Hi, I have created a test specification from Restlet as below to illustrate the issue.

{
  "swagger": "2.0",
  "info": {
    "description": "No description",
    "version": "1.0.0",
    "title": "Test"
  },
  "consumes": [
    "application/json"
  ],
  "produces": [
    "application/json"
  ],
  "paths": {
    "/test/{test_id}": {
      "get": {
        "summary": "Gets the specific test object",
        "parameters": [],
        "responses": {
          "200": {
            "description": "Status 200",
            "schema": {
              "$ref": "#/definitions/_test_object"
            }
          }
        }
      },
      "parameters": [
        {
          "name": "test_id",
          "in": "path",
          "required": true,
          "type": "string"
        }
      ]
    }
  },
  "definitions": {
    "_test_object": {
      "type": "object",
      "required": [
        "price",
        "test_description",
        "test_id"
      ],
      "properties": {
        "test_id": {
          "type": "string"
        },
        "test_description": {
          "type": "string"
        },
        "price": {
          "type": "number"
        }
      }
    }
  }
}

the snippet of the output below shows the issue. It is adding a "}" in the middle of the function names (e.g. TestId}Async) .It looks like it is due to the underscore in the path definition e.g. /test/{test_id}. If I take the underscore out (/test/{testid}), then the code generates OK.

 /// <summary>Gets the specific test object</summary>
        /// <returns>Status 200</returns>
        /// <exception cref="SwaggerException">A server side error occurred.</exception>
        public System.Threading.Tasks.Task<_test_object>TestId}Async(string test_id)
        {
            return TestId}Async(test_id, System.Threading.CancellationToken.None);
        }
    
        /// <summary>Gets the specific test object</summary>
        /// <returns>Status 200</returns>
        /// <exception cref="SwaggerException">A server side error occurred.</exception>
        /// <param name="cancellationToken">A cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
        public async System.Threading.Tasks.Task<_test_object> TestId}Async(string test_id, System.Threading.CancellationToken cancellationToken)
        {
            if (test_id == null)
                throw new System.ArgumentNullException("test_id");