How to use the refextract.extract_references_from_string function in refextract

def refextract_text():
    """Run refextract on a piece of text."""
    with local_refextract_kbs_path() as kbs_path:
        extracted_references = extract_references_from_string(
            request.json['text'],
            override_kbs_files=kbs_path,
            reference_format=u'{title},{volume},{page}'
        )
    references = map_refextract_to_schema(extracted_references)
    references = match_references(references)
    return jsonify(references)

def extract_references_from_text(text, source=None, custom_kbs_file=None):
    """Extract references from text and return in INSPIRE format."""
    with local_refextract_kbs_path() as kbs_path:
        extracted_references = extract_references_from_string(
            text,
            override_kbs_files=kbs_path,
            reference_format=u'{title},{volume},{page}',
        )

    return map_refextract_to_schema(extracted_references, source=source)