'anchors the image to the given cell
optional parameter anchortype supports \'absolute\' or \'oneCell\''

def anchor(self, cell, anchortype='absolute'):

    self.drawing.anchortype = anchortype
    if (anchortype == 'absolute'):
        (self.drawing.left, self.drawing.top) = cell.anchor
        return ((cell.column, cell.row), cell.parent.point_pos((self.drawing.top + self.drawing.height), (self.drawing.left + self.drawing.width)))
    elif (anchortype == 'oneCell'):
        self.drawing.anchorcol = (column_index_from_string(cell.column) - 1)
        self.drawing.anchorrow = (cell.row - 1)
        return ((self.drawing.anchorcol, self.drawing.anchorrow), None)
    else:
        raise ValueError(('unknown    anchortype    %s' % anchortype))
