It means the value of data is None. or empty or NaN

def write_file(data, filename): # creates file and writes list to it with open(filename, 'wb') as outfile: writer = csv.writer(outfile) for row in data: # ABOVE ERROR IS THROWN HERE writer.writerow(row)

conn.execute("select name from artists order by name")
row = conn.fetchall() #in mysql we must use fetchall() function inorder to split dataa beecause remember it is different from sqlite we use cursor here
for artist in row: artistlist.insert(tkinter.END, artist[0])