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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 _initial_guess(self):
 """ Quadratic fit to get an initial guess for the parameters. Returns: tuple: (e0, b0, b1, v0) """

        a, b, c = np.polyfit(self.volumes, self.energies, 2)
        self.eos_params = [a, b, c]

        v0 = -b/(2*a)
        e0 = a*(v0**2) + b*v0 + c
        b0 = 2 * a * v0
        b1 = 4  # b1 is usually a small number like 4

        vmin, vmax = min(self.volumes), max(self.volumes)

        if not vmin < v0 and v0 < vmax:
            raise EOSError('The minimum volume of a fitted parabola is '
                           'not in the input volumes\n.')

        return e0, b0, b1, v0