I get "TypeError: exceptions must derive from BaseException" even though I did define it

according to python documents, Exception is derived from BaseExceptions and I should use it for user defined exceptions. so I have: ``` class VisaIOError(Exception): def __init__(self, error_code): abbreviation, description = _completion_and_error_messages[error_code] Error.__init__(self, abbreviation + ": " + description) self.error_code = error_code ``` And ``` raise(visa_exceptions.VisaIOError, status) ``` but I get (trackback snippet): ``` File "C:\Python32\Lib\site-packages\pyvisa\vpp43.py", line 400, in check_status raise(visa_exceptions.VisaIOError, status) TypeError: exceptions must derive from BaseException ``` Note: I am converting code from python 27 to 32