def Ky(beta_liq, beta_vapor, m_distrib):
    """
    Calculates the masstransfer coefficent Ky.
    Parameters
    ----------
    beta_liq : float
        The masstransfer coefficent beta of liquid, [kmol / (m**2 * s)]
    beta_vapor : float
        The masstransfer coefficent beta of vapor, [kmol / (m**2 * s)]
    m_distrib : float
        The distribution coefficient, [dismensionless]
    Returns
    -------
    Ky : float
        The masstransfer coefficent Ky, [kmol / (m**2 * s)]
    References
    ----------
    Дытнерский, стр.194 формула 5.8
    """        
    return ((1 / beta_vapor) + (m_distrib / beta_liq))**(-1)