Generates a new instance of :class:`maspy.proteindb.PeptideSequence`
        from a decoded JSON object (as generated by
        :func:`maspy.proteindb.PeptideSequence._reprJSON()`).

        :param jsonobject: decoded JSON object

        :returns: a new instance of :class:`PeptideSequence`

def _fromJSON(cls, jsonobject):
        """Generates a new instance of :class:`maspy.proteindb.PeptideSequence`
        from a decoded JSON object (as generated by
        :func:`maspy.proteindb.PeptideSequence._reprJSON()`).

        :param jsonobject: decoded JSON object

        :returns: a new instance of :class:`PeptideSequence`
        """
        newInstance = cls(jsonobject[0], jsonobject[1])
        newInstance.isUnique = jsonobject[2]
        newInstance.proteins = set(jsonobject[3])
        newInstance.proteinPositions = jsonobject[4]
        return newInstance