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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 get_partial_text(fulltext):
 """Return a short version of the fulltext used with partial matching mode. The version is composed of 20% in the beginning and 20% in the middle of the text. """

    def _get_index(x):
        return int(float(x) / 100 * len(fulltext))

    partial_text = [
        fulltext[_get_index(start):_get_index(end)]
        for start, end in current_app.config[
            "CLASSIFIER_PARTIAL_TEXT_PERCENTAGES"
        ]
    ]

    return "\n".join(partial_text)