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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 to_array(self):
 """ Serializes this Invoice to a dictionary. :return: dictionary representation of this object. :rtype: dict """

        array = super(Invoice, self).to_array()
        array['title'] = u(self.title)  # py2: type unicode, py3: type str
        array['description'] = u(self.description)  # py2: type unicode, py3: type str
        array['start_parameter'] = u(self.start_parameter)  # py2: type unicode, py3: type str
        array['currency'] = u(self.currency)  # py2: type unicode, py3: type str
        array['total_amount'] = int(self.total_amount)  # type int
        return array