How are the arguments of the open() function decoded?

Question

Python

Greetings
In Python there is an open() function and the function has opening methods:
r - read (read)
w - write (write)
a - add (append)
x - create and write (?)
+ others
I don't understand why "x". How is it deciphered or not?

Answer 1

x is a synonym for the O_EXCL attribute of the open system call.
man open.