class_docstr: Class for writing mat5 files 
code: def write_file_header(self):
      # write header
      hdr = np.zeros((), NDT_FILE_HDR)
      hdr["description"] = (
          f"MATLAB 5.0 MAT-file Platform: {os.name}, "
          f"Created on: {time.asctime()}"
      )
      hdr["version"] = 0x0100
      hdr["endian_test"] = np.ndarray(
          shape=(), dtype="S2", buffer=np.uint16(0x4D49)
      )
      self.file_stream.write(hdr.tobytes())
  
imports: import os
  import time
  import sys
  import zlib
  from io import BytesIO
  import warnings
  import numpy
  import scipy.sparse
  from ._byteordercodes import native_code, swapped_code
  from ._miobase import MatFileReader, docfiller, matdims, read_dtype, arr_to_chars, arr_dtype_number, MatWriteError, MatReadError, MatReadWarning
  from ._mio5_utils import VarReader5
  from ._mio5_params import MatlabObject, MatlabFunction, MDTYPES, NP_TO_MTYPES, NP_TO_MXTYPES, miCOMPRESSED, miMATRIX, miINT8, miUTF8, miUINT32, mxCELL_CLASS, mxSTRUCT_CLASS, mxOBJECT_CLASS, mxCHAR_CLASS, mxSPARSE_CLASS, mxDOUBLE_CLASS, mclass_info, mat_struct
  from ._streams import ZlibInputStream
label_desc: Use image node_id 2 for calling the MatFile5Writer obj's underlying member method code with example usage: obj.write_file_header() without return types