code: def write_meta_header(filename, meta_dict):
      
      header = ''
      # do not use tags = meta_dict.keys() because the order of tags matters
      for tag in MHD_TAGS:
          if tag in meta_dict.keys():
              header += '{} = {}\n'.format(tag, meta_dict[tag])
  
      with open(filename, 'w') as f:
          f.write(header)
docs: Write the content of the `meta_dict` into `filename`.
  
      Parameters
      ----------
      filename: str
          Path to the output file
  
      meta_dict: dict
          Dictionary with the fields of the metadata .mhd file