class_docstr: Utility around Python `struct` module (https://docs.python.org/3.6/library/struct.html)
   that allows to access and modify `_fields` like an ordinary object attributes
   and read/write their values from/into the buffer in C struct like format.
  Similar approach of declaring _fields_ with corresponding C types can be found in
  Python `ctypes` module (https://docs.python.org/3/library/ctypes.html).
class_docstr_tok: ["Utility","around","Python","`","struct","`","module","(","https",":","\/\/docs.python.org\/3.6\/library\/struct.html",")","that","allows","to","access","and","modify","`","_fields","`","like","an","ordinary","object","attributes","and","read\/write","their","values","from\/into","the","buffer","in","C","struct","like","format",".","Similar","approach","of","declaring","_fields_","with","corresponding","C","types","can","be","found","in","Python","`","ctypes","`","module","(","https",":","\/\/docs.python.org\/3\/library\/ctypes.html",")","."]
code: def setup_struct(cls):
      if "_struct_desc" not in cls.__dict__:
          cls._struct_desc = "@" + "".join(
              field_type for _, field_type in cls._fields
          )
          cls._struct = struct.Struct(cls._struct_desc)
  
file_path: DALI/dali/python/nvidia/dali/_multiproc/struct_message.py
imports: import struct
label_desc: Use image node_id 2 for calling the Structure obj's underlying member method code with example usage: obj.setup_struct(cls) without return types