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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 calculate_single_terms(self):
 """Lines of model method with the same name."""

        lines = self._call_methods('calculate_single_terms',
                                   self.model.PART_ODE_METHODS)
        if lines:
            lines.insert(1, ('        self.numvars.nmb_calls ='
                             'self.numvars.nmb_calls+1'))
        return lines