发现差异时，difflib.HtmlDiff.make_file错误

Question

以下提到的代码在python 3.7中的HtmlDiff处引发错误

错误：可能是HtmlDiff，而是列表[str]

    import subprocess
    import difflib
    subprocess.call([r'C:\test\test1\testapp.bat'])
    standard_file="C:\test\test1\test.plmxml"
    output_file="C:\test\test1\output\eco.plmxml"
    standard_file_lines=open(standard_file).readlines()
    output_file_lines=open(output_file).readlines()
difference=difflib.HtmlDiff.make_file(standard_file_lines,output_file_lines,"standard_file","current_execution_result")   
    difference_report=open("C:\test\test1\reportoutput\report.html",'w')

difference_report.write(difference)
difference_report.close()

谁能让我知道为什么makefile出错？