return a created excel file with flask

I am creating a excel file using openpyxl which I would like to return as a file download (so not saving locally).

I can create the excel file fine and save it to disk. However, I cannot get this file to download.

Attempt 1:

import flask_excel as excel

...

create_excel_sheet(data) # internally save the sheet with name sheet.xlsx

output = excel.make_response()
output.headers["Content-Disposition"] = "attachment; filename=" + \
                                        'sheet.xlsx'
output.headers["Content-type"] = "application/vnd.openxmlformats-\
officedocument.spreadsheetml.sheet"

return output

This returns an empty text file with name sheet.xlsx

Attempt 2: wb = create_excel_sheet(data) # return openpyxl workbook

output = excel.make_response(wb)
output.headers["Content-Disposition"] = "attachment; filename=" + \
                                        'sheet.xlsx'
output.headers["Content-type"] = "application/vnd.openxmlformats-\
officedocument.spreadsheetml.sheet"

return output

I don't want to use pyexcel for the data as I need openpyxl to create a fancy excel sheet. Obviously if pyexcel and openpyxl communicated that would be fine.

any thoughts?

Cheers, Mike

Based on Charlie Clark's hint, I finally settled on the following solution.

output = make_response(create_sheet(data))
output.headers["Content-Disposition"] = "attachment; filename=" + \
                                        "sheet.xlsx"
output.headers["Content-type"] = \
    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"

where

def create_sheet(data):

returns

return save_virtual_workbook(wb)