def _plot_transform_pairs(fCI, r, k, axes, tit):
    r"""Plot the input transform pairs."""

    # Plot lhs
    plt.sca(axes[0])
    plt.title('|' + tit + ' lhs|')
    for f in fCI:
        if f.name == 'j2':
            lhs = f.lhs(k)
            plt.loglog(k, np.abs(lhs[0]), lw=2, label='j0')
            plt.loglog(k, np.abs(lhs[1]), lw=2, label='j1')
        else:
            plt.loglog(k, np.abs(f.lhs(k)), lw=2, label=f.name)
    if tit != 'fC':
        plt.xlabel('l')
    plt.legend(loc='best')

    # Plot rhs
    plt.sca(axes[1])
    plt.title('|' + tit + ' rhs|')

    # Transform pair rhs
    for f in fCI:
        if tit == 'fC':
            plt.loglog(r, np.abs(f.rhs), lw=2, label=f.name)
        else:
            plt.loglog(r, np.abs(f.rhs(r)), lw=2, label=f.name)

    # Transform with Key
    for f in fCI:
        if f.name[1] in ['0', '1', '2']:
            filt = j0j1filt()
        else:
            filt = sincosfilt()
        kk = filt.base/r[:, None]
        if f.name == 'j2':
            lhs = f.lhs(kk)
            kr0 = np.dot(lhs[0], getattr(filt, 'j0'))/r
            kr1 = np.dot(lhs[1], getattr(filt, 'j1'))/r**2
            kr = kr0+kr1
        else:
            kr = np.dot(f.lhs(kk), getattr(filt, f.name))/r

        plt.loglog(r, np.abs(kr), '-.', lw=2, label=filt.name)

    if tit != 'fC':
        plt.xlabel('r')

    plt.legend(loc='best')
r"""Plot the input transform pairs.