code: def write(self, output_file):
      output_file.flush()
      header_offset = output_file.tell()
      # First, write the magic number (uint64, 8 bytes)
      output_file.write(struct.pack("<Q", MAGIC_NUMBER))
      # Next is the number of chunks (uint32, 4 bytes)
      output_file.write(struct.pack("<I", len(self.chunks)))
      # Finally the number of input streams (uint32, 4 bytes)
      output_file.write(struct.pack("<I", len(self.converters)))
      for converter in self.converters.values():
          converter.write_header(output_file)
      # write the chunk table
      for chunk in self.chunks:
          # int64: start offset for chunk
          output_file.write(struct.pack("<q", chunk.offset))
          # uint32: number of sequences in the chunk
          output_file.write(struct.pack("<I", chunk.num_sequences()))
          # uint32: number of samples in the chunk
          output_file.write(struct.pack("<I", chunk.num_samples()))
  
      output_file.write(struct.pack("<q", header_offset))
  
imports: import sys
  import argparse
  import struct
  import os
  from collections import OrderedDict
label_desc: Use image node_id 3 for calling the Header obj's underlying member method code with example usage: obj.write(output_file) without return types