健壮地获取对象的[[Prototype]]
^1.0.1
^1.0.0
^0.17.2
^21.1.1
^0.2.3
^5.8.0
^2.5.0
=8.8.0
^0.0.19
^2.0.1
^0.3.1
^10.3.2
^2.0.0
^5.9.0
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