':return: timestamped file name
:rtype: str'

def timestamped_file(self):

    subdir = self.subdir
    fprefix = self.fprefix
    if subdir:
        if (not os.path.exists(subdir)):
            os.mkdir(subdir)
    fname = os.path.join(subdir, fprefix)
    fmt = '%Y%m%d-%H%M%S'
    timestamp = datetime.datetime.now().strftime(fmt)
    if self.gzip_compress:
        suffix = '.gz'
    else:
        suffix = ''
    outfile = '{0}.{1}.json{2}'.format(fname, timestamp, suffix)
    return outfile
