TypeError: encoding or errors without a string argument

This error just means the thing you're passing to bytes (the string you want converted to a byte sequence) is not in fact a string. It does not specifically mean that the argument is already of type bytes, just that it isn't a string.

>>> bytes(b"", encoding="utf-8")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: encoding without a string argument
>>> bytes(None, encoding="utf-8")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: encoding without a string argument
>>> bytes(12, encoding="utf-8")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: encoding without a string argument

It seems your datas is already in bytes format, so to turn it into UTF-8 strings, you have to use str, not bytes! Also, you have to convert each element from datas individually, not the entire list at once. Finally, if you want to add datas as one row to out.csv, you have to use writerow, whereas writerows would write all the rows at once, and accordinly would expect a list of lists.

Depending on your OS, you might also have to specify the encoding when opening the file. Otherwise it will use the OS' default encoding, which might be something entirely different.

This seems to do what you want. The result is a CSV file with one row¹ of data in UTF-8 format, and the \xc3\x97 is decoded to ×.

import csv
with open(r"out.csv", "w", encoding='UTF-8') as w:
    writer = csv.writer(w)
    writer.writerow([str(d, 'UTF-8') for d in datas])

---

¹⁾ Note that the last item in datas contains some line breaks, and thus will be split onto several lines. This is probably not what you want. Or is this a glitch in your datas list?