code: def _context_string(context):
      
      msg = 'Code block context:\n            '
      lines = ['Selective arithmetic coding bypass:  {0}',
               'Reset context probabilities on coding pass boundaries:  {1}',
               'Termination on each coding pass:  {2}',
               'Vertically stripe causal context:  {3}',
               'Predictable termination:  {4}',
               'Segmentation symbols:  {5}']
      msg += '\n            '.join(lines)
      msg = msg.format(((context & 0x01) > 0),
                       ((context & 0x02) > 0),
                       ((context & 0x04) > 0),
                       ((context & 0x08) > 0),
                       ((context & 0x10) > 0),
                       ((context & 0x20) > 0))
      return msg
docs: Produce a string to represent the code block context