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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 process_json_file(file_path, pmid=None, extra_annotations=None, add_grounding=True):
 """Extracts statements from the given ISI output file. Parameters file_path : str The ISI output file from which to extract statements pmid : int The PMID of the document being preprocessed, or None if not specified extra_annotations : dict Extra annotations to be added to each statement from this document (can be the empty dictionary) add_grounding : Optional[bool] If True the extracted Statements' grounding is mapped """

    logger.info('Extracting from %s' % file_path)
    with open(file_path, 'rb') as fh:
        jd = json.load(fh)
        ip = IsiProcessor(jd, pmid, extra_annotations)
        ip.get_statements()
        if add_grounding:
            ip.add_grounding()
        return ip