def METHOD_NAME(data, mapfunc=lambda x: x):
    """Reflect a variable about midplane
    Optionally supply a mapping function"""
    data2 = np.zeros([tsize, npsi])
    # Copy the original data
    for i in np.arange(ntheta):
        data2[i, :] = data[i, :]
    # Now fill in the remainder
    for i in np.arange(ntheta, tsize):
        t0 = tsize - 1 - i
        data2[i, :] = mapfunc(data[t0, :])
    return data2