code: def parse(cls, fptr, offset=0, length=0):
          
          main_header_offset = fptr.tell()
          if config.get_option('parse.full_codestream'):
              codestream = Codestream(fptr, length, header_only=False)
          else:
              codestream = None
          box = cls(codestream, main_header_offset=main_header_offset,
                    length=length, offset=offset)
          box._filename = fptr.name
          box._length = length
          return box
docs: Parse a codestream box.
  
          Parameters
          ----------
          fptr : file
              Open file object.
          offset : int
              Start position of box in bytes.
          length : int
              Length of the box in bytes.
  
          Returns
          -------
          ContiguousCodestreamBox
              Instance of the current contiguous codestream box.