code: def bz2open(cls, name, mode="r", fileobj=None, compresslevel=9, **kwargs):
          
          if len(mode) > 1 or mode not in "rw":
              raise ValueError("mode must be 'r' or 'w'.")
  
          try:
              import bz2
          except ImportError:
              raise CompressionError("bz2 module is not available")
  
          if fileobj is not None:
              fileobj = _BZ2Proxy(fileobj, mode)
          else:
              fileobj = bz2.BZ2File(name, mode, compresslevel=compresslevel)
  
          try:
              t = cls.taropen(name, mode, fileobj, **kwargs)
          except (IOError, EOFError):
              fileobj.close()
              raise ReadError("not a bzip2 file")
          t._extfileobj = False
          return t
docs: Open bzip2 compressed tar archive name for reading or writing.
             Appending is not allowed.