'Show or hide the grid for either axis.
**Arguments:**
x               (bool) Whether to show the X grid
y               (bool) Whether to show the Y grid
alpha           (0.0-1.0) Opacity of the grid'

def showGrid(self, x=None, y=None, alpha=None):

    if ((x is None) and (y is None) and (alpha is None)):
        raise Exception('Must    specify    at    least    one    of    x,    y,    or    alpha.')
    if (x is not None):
        self.ctrl.xGridCheck.setChecked(x)
    if (y is not None):
        self.ctrl.yGridCheck.setChecked(y)
    if (alpha is not None):
        v = (np.clip(alpha, 0, 1) * self.ctrl.gridAlphaSlider.maximum())
        self.ctrl.gridAlphaSlider.setValue(v)
