def METHOD_NAME(img):
    """Remove the alpha channel from a ``vtk.vtkImageData``.
    Parameters
    ----------
    img : vtk.vtkImageData
        The input image data with an alpha channel.
    Returns
    -------
    pyvista.ImageData
        The output image data with the alpha channel removed.
    """
    ec = _vtk.vtkImageExtractComponents()
    ec.SetComponents(0, 1, 2)
    ec.SetInputData(img)
    ec.Update()
    return pyvista.wrap(ec.GetOutput())