def lame_parameters(plane_strain: bool = False):
    """
    Returns the Lame parameters for plane stress or plane strain.
    Return type is lambda functions
    """
    def mu(E, nu):
        return E / (2 * (1 + nu))

    if plane_strain:
        def lmbda(E, nu):
            return E * nu / ((1 + nu) * (1 - 2 * nu))
        return mu, lmbda
    else:
        def lmbda(E, nu):
            return E * nu / ((1 + nu) * (1 - nu))
        return mu, lmbda