Write newline to csv in Python

I want to end each interation of a for loop with writing a new line of content (including newline) to a csv file. I have this: ``` # Set up an output csv file with column headers with open('outfile.csv','w') as f: f.write("title; post") f.write("\n") ``` This does not appear to write an actual \n (newline) the file. Further: ``` # Concatenate into a row to write to the output csv file csv_line = topic_title + ";" + thread_post with open('outfile.csv','w') as outfile: outfile.write(csv_line + "\n") ``` This, also, does not move the cursor in the outfile to the next line. Each new line, with every iteration of the loop, just overwrites the most recent one. I also tried `outfile.write(os.linesep)` but did not work.