Error from xlsm file when adding strings to a xltm template

Issue #594 resolved
Elizabeth Gene
created an issue

This sample code:

from openpyxl import load_workbook
wb = load_workbook('template.xltm', keep_vba=True) 
ws = 
cell = ws.cell(column=1, row=1, value='42')'sample_book.xlsm') 

produces a corrupted spreadsheet when run on Ubuntu with these versions: Python 2.7.6 lxml Version: 3.5.0 * openpyxl Version: 2.3.3

If the value is changed to an int, the spreadsheet is fine.