Unicode String types are a handy Python feature that allows you to decode encoded Strings and forget about the encoding until you need to write or transmit the data. Python tries to convert a byte-array (a bytes which it assumes to be a utf-8-encoded string) to a unicode string (str). This process of course is a decoding according to utf-8 rules. When it tries this, it encounters a python byte sequence which is not allowed in utf-8-encoded strings (namely this 0xff at position 0). One simple way to avoid this error is to encode such strings with encode() function as follows (if a is the string with non-ascii character):
a.encode('utf-8').strip()
Or
Use encoding format ISO-8859-1 to solve the issue.