inp_fn: str, required.
       Path to file from which to read Open IE extractions in Open IE4's format.
    domain: str, required.
       Domain to be used when writing CoNLL format.
    out_fn: str, required.
       Path to file to which to write the CoNLL format Open IE extractions.

def main(inp_fn: str,
         domain: str,
         out_fn: str) -> None:
    """
    inp_fn: str, required.
       Path to file from which to read Open IE extractions in Open IE4's format.
    domain: str, required.
       Domain to be used when writing CoNLL format.
    out_fn: str, required.
       Path to file to which to write the CoNLL format Open IE extractions.
    """
    with open(out_fn, 'w') as fout:
        for sent_ls in read(inp_fn):
            fout.write("{}\n\n".format('\n'.join(['\t'.join(map(str,
                                                                pad_line_to_ontonotes(line,
                                                                                      domain)))
                                                  for line
                                                  in convert_sent_to_conll(sent_ls)])))