code: def _write_vvr(self, f, data):
          '''
          Writes a vvr to the end of file "f" with the byte stream "data".
          '''
          f.seek(0, 2)
          byte_loc = f.tell()
          block_size = CDF.VVR_BASE_SIZE64 + len(data)
          section_type = CDF.VVR_
  
          vvr1 = bytearray(12)
          vvr1[0:8] = struct.pack('>q', block_size)
          vvr1[8:12] = struct.pack('>i', section_type)
          f.write(vvr1)
          f.write(data)
  
          return byte_lof _write_vvr(self, f, data):
          '''
          Writes a vvr to the end of file "f" with the byte stream "data".
          '''
          f.seek(0, 2)
          byte_loc = f.tell()
          block_size = CDF.VVR_BASE_SIZE64 + len(data)
          section_type = CDF.VVR_
  
          vvr1 = bytearray(12)
          vvr1[0:8] = struct.pack('>q', block_size)
          vvr1[8:12] = struct.pack('>i', section_type)
          f.write(vvr1)
          f.write(data)
  
          return byte_loc
docs: Writes a vvr to the end of file "f" with the byte stream "data".