def METHOD_NAME():
    def _assert_equal_arrays(a1, a2):
        assert a1.shape == a2.shape
        for ( xtest, xgood ) in zip( a1, a2 ):
            assert( (xtest == xgood) or (np.isnan(xtest) and np.isnan(xgood) ) ) 
    x = np.array([-np.inf, 0.0, 1.0,  2.0  , np.nan,   4.0 , np.inf])
    y = np.array([    1.0, 0.0,-1.0, np.inf,   2.0 , np.nan,   0.0 ])
    pdi = pg.PlotDataItem(x, y)
    dataset = pdi._getDisplayDataset()
    _assert_equal_arrays( dataset.x, x )
    _assert_equal_arrays( dataset.y, y )
    with warnings.catch_warnings(): 
        warnings.simplefilter("ignore")
        x_log = np.log10(x)
        y_log = np.log10(y)
    x_log[ ~np.isfinite(x_log) ] = np.nan
    y_log[ ~np.isfinite(y_log) ] = np.nan
    pdi.setLogMode(True, True)
    dataset = pdi._getDisplayDataset()
    _assert_equal_arrays( dataset.x, x_log )
    _assert_equal_arrays( dataset.y, y_log )