For help, use the python bulk changes in word form, the form of the original font format is modified

Information extracted from the Excel to fill in in the word,
Use their own definition of the replace function, keep good file format is changed, how to optimize this?

If sheetx. Cell (row=1, the column col=). The value!=None:
For the l in range (1, sheetx max_row + 1) :
Old_text=sheetx. Cell (row=l, the column=1). The value
New_text=sheetx. Cell (row=l, the column col=). The value
(old_text replace_text (STR), STR (new_text))