code: def Seek(self, offset, whence=os.SEEK_SET):
      
      if whence == os.SEEK_SET:
        self.offset = offset
      elif whence == os.SEEK_CUR:
        self.offset += offset
      elif whence == os.SEEK_END:
        self.offset = self.size + offset
      else:
        raise ValueError("Illegal whence value %s" % whence)
docs: Seek to an offset in the file.