python 2.7 unicode writer robust to NoneType -

i hoping use unicodewriter the official examples not hiccup on unicode data when trying csv write. however, if have blanks/missing/nan in list should row, error:

    self.writer.writerow([s.encode("utf-8") s in row]) attributeerror: 'nonetype' object has no attribute 'encode' 

is there easy fix?

i repeat 'official code' below:

class unicodewriter:     """     csv writer write rows csv file "f",     encoded in given encoding.     """      def __init__(self, f, dialect=csv.excel, encoding="utf-8", **kwds):         # redirect output queue         self.queue = cstringio.stringio()         self.writer = csv.writer(self.queue, dialect=dialect, **kwds)         self.stream = f         self.encoder = codecs.getincrementalencoder(encoding)()      def writerow(self, row):         self.writer.writerow([s.encode("utf-8") s in row])         # fetch utf-8 output queue ...         data = self.queue.getvalue()         data = data.decode("utf-8")         # ... , reencode target encoding         data = self.encoder.encode(data)         # write target stream         self.stream.write(data)         # empty queue         self.queue.truncate(0)      def writerows(self, rows):         row in rows:             self.writerow(row) 

a previous question (though string conversion of numbers) solved problem too, see this answer. add conversion unicode: self.writer.writerow([unicode(s).encode("utf-8") s in row])