'Return an RGB(A) lookup table (ndarray).
**Arguments:**
nPts            The number of points in the returned lookup table.
alpha           True, False, or None - Specifies whether or not alpha values are included
in the table.If alpha is None, alpha will be automatically determined.'

def getLookupTable(self, nPts, alpha=None):

    if (alpha is None):
        alpha = self.usesAlpha()
    if alpha:
        table = np.empty((nPts, 4), dtype=np.ubyte)
    else:
        table = np.empty((nPts, 3), dtype=np.ubyte)
    for i in range(nPts):
        x = (float(i) / (nPts - 1))
        color = self.getColor(x, toQColor=False)
        table[i] = color[:table.shape[1]]
    return table
