Angular 类型为'的参数；文件'；不可分配给类型为'；文件'；。财产'；内容'；类型'中缺少；文件'；

出现错误

Downloadutil.downloadReport（项）

是否可以添加有关问题的正确说明？实际上，我在service.ts文件中缺少导入语句。是否可以添加有关问题的正确说明？实际上，我在service.ts文件中缺少导入语句。

// Import statements
import {DownloadUtil} from "../../shared/util/download/download-util";

// Code sample where error is occurring
downloadReport() {
    this.loading = true;
    this.translate.get('EMPLOYEE_SHIFT_REPORT.retrievingReport').subscribe(response => {
        this.loadingMessage = response;
    });
    this.employeeShiftReportService.downloadReport(this.searchRequest).subscribe(item => {
        this.loading = false;
        //this is where error is occurring  
        DownloadUtil.downloadReport(item);
    }, error => {
        this.loading = false;
        this.loadingMessage = null;
    });
}