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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 _mass_from_knownmass_eta(known_mass, eta, known_is_secondary=False, force_real=True):
 r"""Returns the other component mass given one of the component masses and the symmetric mass ratio. This requires finding the roots of the quadratic equation: .. math:: \eta m_2^2 + (2\eta - 1)m_1 m_2 + \eta m_1^2 = 0. This has two solutions which correspond to :math:`m_1` being the heavier mass or it being the lighter mass. By default, `known_mass` is assumed to be the heavier (primary) mass, and the smaller solution is returned. Use the `other_is_secondary` to invert. Parameters known_mass : float The known component mass. eta : float The symmetric mass ratio. known_is_secondary : {False, bool} Whether the known component mass is the primary or the secondary. If True, `known_mass` is assumed to be the secondary (lighter) mass and the larger solution is returned. Otherwise, the smaller solution is returned. Default is False. force_real : {True, bool} Force the returned mass to be real. Returns ------- float The other component mass. """

    roots = numpy.roots([eta, (2*eta - 1)*known_mass, eta*known_mass**2.])
    if force_real:
        roots = numpy.real(roots)
    if known_is_secondary:
        return roots[roots.argmax()]
    else:
        return roots[roots.argmin()]