from docxcompose.composer import Composer
from docx import Document as Document_compose
#filename_master is name of the file you want to merge the docx file into
master = Document_compose(filename_master)
composer = Composer(master)
#filename_second_docx is the name of the second docx file
doc2 = Document_compose(filename_second_docx)
#append the doc2 into the master using composer.append function
composer.append(doc2)
#Save the combined docx with a name
composer.save("combined.docx")