AttributeError: '_io.TextIOWrapper' object has no attribute 'decode'

This error occurs when you try to use the decode() method on a text file that has already been opened in Python 3.x. The decode() method is used to convert bytes to strings, but in Python 3.x, text files are already stored as strings by default. Therefore, the decode() method is not needed and cannot be used on text files.

To fix this error, you should remove any calls to the decode() method on text files in your code. If you need to read binary files and convert them to strings, you can use the read() method with the appropriate encoding parameter. For example:

with open('file.txt', 'rb') as f:
    contents = f.read().decode('utf-8')

In this example, the file is opened in binary mode ('rb') and the read() method is used to read the contents of the file as bytes. The decode() method is then used to convert the bytes to a string using the UTF-8 encoding.