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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def convert_sent_dict_to_conll(sent_dic, domain) -> str: """ Given a dictionary from sentence -> extractions, return a corresponding CoNLL representation. """

    return '\n\n'.join(['\n'.join(['\t'.join(map(str, pad_line_to_ontonotes(line, domain)))
                                   for line in convert_sent_to_conll(sent_ls)])
                        for sent_ls
                        in sent_dic.iteritems()])