code: def _struct_unpack(fin, fmt):
      num_bytes = struct.calcsize(fmt)
      return struct.unpack(fmt, fin.read(num_bytes))
  
imports: import collections
  import gzip
  import io
  import logging
  import struct
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: _struct_unpack(fin, fmt) and returns: struct