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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 _initialize_integrator(self, t0, y0, integrator, **kwargs):
 """Initializes the integrator prior to integration."""

        # set the initial condition
        self.set_initial_value(y0, t0)

        # select the integrator
        self.set_integrator(integrator, **kwargs)