code: def read_float64(self) -> float:
      res = struct.unpack(
          "=d", self._memview[self._offset : self._offset + 8]
      )[0]
      self._offset += 8
      return res
  
imports: import struct
  from typing import Union
label_desc: Use image node_id 6 for calling the ByteReader obj's underlying member method code with example usage: obj.read_float64() and returns: res