code: def copy_header(header_file, in_file, keep_dtype=True):
      """Copy header from a reference image onto another image."""
      hdr_img = nb.load(header_file)
      out_img = nb.load(in_file, mmap=False)
      hdr = hdr_img.header.copy()
      if keep_dtype:
          hdr.set_data_dtype(out_img.get_data_dtype())
  
      new_img = out_img.__class__(out_img.dataobj, None, hdr)
      if not keep_dtype:
          new_img.set_data_dtype(hdr_img.get_data_dtype())
  
      new_img.to_filename(in_file)
      return in_file
  
label_desc: Use image node_id 1 for calling a global function with example usage: copy_header(header_file, in_file, keep_dtype) and returns: in_file