TypeError: write() got an unexpected keyword argument 'file'

[Toral-Manvar]

When I am trying to run gmconvert with test file, I am getting following error:

root@bio1-c:/gmconvert-master# python cli/gmconvert.py --input=test.genemapper --output=test1.xls
Traceback (most recent call last):
File "cli/gmconvert.py", line 211, in
main()
File "cli/gmconvert.py", line 207, in main
write_records_to_excel(options.output, population, markers)
File "cli/gmconvert.py", line 199, in write_records_to_excel
ew.save(filename = output)
File "/usr/local/lib/python2.7/dist-packages/openpyxl-1.1.0-py2.7.egg/openpyxl/writer/excel.py", line 51, in save
content = write_string_table(string_table = shared_string_table))
File "/usr/local/lib/python2.7/dist-packages/openpyxl-1.1.0-py2.7.egg/openpyxl/writer/strings.py", line 61, in write_string_table
return get_document_content(xml_node = root)
File "/usr/local/lib/python2.7/dist-packages/openpyxl-1.1.0-py2.7.egg/openpyxl/shared/xmltools.py", line 35, in get_document_content
ElementTree(xml_node).write(file = fl, encoding = 'UTF-8')
TypeError: write() got an unexpected keyword argument 'file'

However, when I just use command "python gmconvert.py", it displays usage without any error.
Version of Python which I am using is "Python 2.7.6".

Please help.