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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 mass2_from_mass1_eta(mass1, eta, force_real=True):
 """Returns the secondary mass from the primary mass and symmetric mass ratio. """

    return mass_from_knownmass_eta(mass1, eta, known_is_secondary=False,
                                   force_real=force_real)