can't set colorbar position

I have included a colorbar in my code.
cb = mlab.colorbar(orientation='vertical', nb_labels=6, label_fmt=fmt)

When I tried to set colorbar position and scale with the following lines, none of them works. However, I can drag and move the colorbar in plot window, and the dragging or scaling actually changed the values of 'cb.scalar_bar.position_coordinate.value', 'cb.scalar_bar.actual_position_coordinate.value', 'cb.scalar_bar.position2_coordinate.value', and 'cb.scalar_bar.actual_position2_coordinate.value'.

Thanks!

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cb.scalar_bar.position = (0.88, 0.16)
cb.scalar_bar.position_coordinate.value = np.array([0.88, 0.16, 0.])
cb.scalar_bar.actual_position_coordinate.value = np.array([0.88, 0.16, 0.])
cb.scalar_bar.position2 = (0.1, 0.4)
cb.scalar_bar.position2_coordinate.value = np.array([0.1, 0.4, 0.])
cb.scalar_bar.actual_position2_coordinate.value = np.array([0.1, 0.4, 0.])