Adding variable write_rich_string format properties to a text with Python xlsxwriter

I want to generate an Excel file with several strings across the cells, and mark some parts of each string with a set of colors.

This is an example if I just wanted to mark a fixed part of a single text:

import xlsxwriter

outfile  = xlsxwriter.Workbook('file.xlsx')
sheet    = outfile.add_worksheet()
bold_red = outfile.add_format({'bold': True,'font_color':'red', 'underline': True})

sheet.write_rich_string(0,0,"This text in black, ",bold_red,"this one in red & bold, ","and this -probably- in other color")

outfile.close()

The result is an Excel file with a cell this text in "A1":

I tried passing a variable input to write_rich_string, but the content of bold_red is xlsxwriter.format.Format and cannot concatenate with strings.

This is how it looks without the colors:

This is the expected output:

In this link by @jmcnamara I found the answer:

"If you have formats and segments in a list you can add them like this, using the standard Python list unpacking syntax:"

segments = ['This is ', bold, 'bold', ' and this is ', blue, 'blue']
worksheet.write_rich_string('A9', *segments)

So for each "Text" in my dataframe, will get its pattern for coloring from a external key. Then form a list with pieces of text and formats embedded. Finally pass this list as a parameter to write_rich_string.