+def write_string(s, out=None):
+ if out is None:
+ out = sys.stderr
+ assert type(s) == type(u'')
+
+ if ('b' in getattr(out, 'mode', '') or
+ sys.version_info[0] < 3): # Python 2 lies about mode of sys.stderr
+ s = s.encode(preferredencoding(), 'ignore')
+ out.write(s)
+ out.flush()
+
+