write() argument must be str, not None

This error occurs when you try to pass a None value as an argument to the write() method, which expects a string as input.

To fix this error, make sure that the argument you're passing to the write() method is not None. You can do this by checking the value of the variable or expression you're passing as an argument.

For example:

my_string = None
if my_string is not None:
    file.write(my_string)

In this example, we check if the value of my_string is not None before passing it to the write() method.

Alternatively, you can set a default value for the argument to avoid passing None:

def my_function(my_string=None):
    if my_string is not None:
        file.write(my_string)

In this example, we set the default value of my_string to None, but check if it's not None before passing it to the write() method.