'**SUMMARY**
Return Grid Lines as a Line Feature Set
**PARAMETERS**
None
**RETURNS**
Grid Lines as a Feature Set
**EXAMPLE**
>>>> img = Image(\'something.png\')
>>>> img.grid([20,20],(255,0,0))
>>>> lines = img.findGridLines()'

def findGridLines(self):

    gridIndex = self.getDrawingLayer(self._gridLayer[0])
    if (self._gridLayer[0] == (-1)):
        print 'Cannot    find    grid    on    the    image,    Try    adding    a    grid    first'
    lineFS = FeatureSet()
    try:
        step_row = (self.size()[1] / self._gridLayer[1][0])
        step_col = (self.size()[0] / self._gridLayer[1][1])
    except ZeroDivisionError:
        return None
    i = 1
    j = 1
    while (i < self._gridLayer[1][0]):
        lineFS.append(Line(self, ((0, (step_row * i)), (self.size()[0], (step_row * i)))))
        i = (i + 1)
    while (j < self._gridLayer[1][1]):
        lineFS.append(Line(self, (((step_col * j), 0), ((step_col * j), self.size()[1]))))
        j = (j + 1)
    return lineFS
