csv.DictWriter has similar problems as csv.DictReader
as described in bug #792558.

The signature of csv.DictWriter.__init__ is:

    def __init__(self, f, fieldnames, restval="",
extrasaction="raise",
                 dialect="excel", *args):

but the docs says:

class DictWriter(csvfile, fieldnames[, restval=""[,
extrasaction='raise'[, dialect='excel'[, fmtparam]]]])

Problems:

1. f != csvfile
2. The constructor does not accept **arguments, which
is a problem to pass along the (one or several)
fmtparam mentioned in the doc.