code: def _missing_double(self, vec):
      v = vec.view(dtype="u1,u1,u2,u4")
      miss = (v["f1"] == 0) & (v["f2"] == 0) & (v["f3"] == 0)
      miss1 = (
          ((v["f0"] >= 0x41) & (v["f0"] <= 0x5A))
          | (v["f0"] == 0x5F)
          | (v["f0"] == 0x2E)
      )
      miss &= miss1
      return miss
  
imports: from datetime import datetime
  import struct
  import warnings
  import numpy
  from pandas.util._decorators import Appender
  import pandas
  from pandas import compat
  from pandas.io.common import BaseIterator, get_filepath_or_buffer
label_desc: Use image node_id 8 for calling the XportReader obj's underlying member method code with example usage: obj._missing_double(vec) and returns: miss