def get_filename(self, kper):
    ext = 'dat'
    if self.binary:
        ext = 'bin'
    return (self.package.name[0] + '_{0:04d}.{1}'.format(kper, ext))
def get_filename(self, kper):
    ext = 'dat'
    if self.binary:
        ext = 'bin'
    return (self.package.name[0] + '_{0:04d}.{1}'.format(kper, ext))