def element_deselect(self, cls, type, value):
'''取消下拉框勾选操作'''
select = Select(self.get_element(cls))
if (type == 'index'):
select.deselect_by_index(value)
elif (type == 'visible_text'):
select.deselect_by_visible_text(value)
elif (type == 'value'):
select.dedeselect_by_value(value)
