Where a defendant could not challenge the calculation of credit for time served at his appeal, as he had failed to exhaust administrative remedies with the Bureau of Prisons first.The 7th U.S. Circuit Court of Appeals affirmed a decision by U.S. District Judge Sharon Johnson Coleman.In June 2016, Maurice Walker was on parole for prior state convictions. Chicago police arrested him after he fled with a gun in hand and attempted to discard the weapon before being apprehended.The following December, a grand jury returned an …