Merge cells after copying a worksheet change original worksheet.

Created originally on Bitbucket by bonapart71 (Andrew Nikolayenkov)

A small example:

#!python

from openpyxl import Workbook
wb = Workbook()
ws1 = wb.active
ws2 = wb.copy_worksheet(ws1)
ws2.merge_cells('A1:C3')
wb.save('test.xlsx')

In the file, you can see that the cells are merged in both sheets - ws1 and w2.