error UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte

Here is an example of how to handle a UnicodeDecodeError caused by an invalid start byte:

    # some code that may raise a UnicodeDecodeError
    with open('file.txt', 'r') as f:
        contents =
except UnicodeDecodeError as e:
    # handle the error
    print(f'Error: {e}')
    # replace invalid bytes with the Unicode Replacement Character (U+FFFD)
    contents = open('file.txt', 'rb').read().decode(errors='replace')
    # do something with the contents

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This will try to open the file and read its contents, but if a UnicodeDecodeError is raised, it will catch the error, print an error message, then read the file in binary mode, decode it using the 'replace' error handler, replacing any invalid bytes with the Unicode Replacement Character (U+FFFD), and then you can do something with the contents.

You can also use 'ignore' as the error handler, it will ignore invalid bytes, But it's not recommended because it can cause loss of information.