op_helper中的is_poly(segm)方法不安全

[xiaoming-master]

问题确认 Search before asking

• 我已经查询历史issue，没有类似需求。I have searched the issues and found no similar feature requests.

需求描述 Feature Description

def is_poly(segm):
assert isinstance(segm, (list, dict)),
"Invalid segm type: {}".format(type(segm))
return isinstance(segm, list)
这玩意儿是不是写得太草率了，就只做了类型判断，segm内部元素格式也不判断，也不验证segm是不是真的Polygon

是否愿意提交PR Are you willing to submit a PR?

• Yes I'd like to help by submitting a PR!

[xiaoming-master]

而且一些op增广gt_poly数据时需要ndarray，一些又需要list类型，有点混乱