TYP: PeriodArray._unbox_scalar
mypy errors with numpy 1.20

pandas/core/arrays/period.py:273: error: Return type "int" of "_unbox_scalar" incompatible with return type "Union[signedinteger[_64Bit], datetime64, timedelta64]" in supertype "DatetimeLikeArrayMixin"  [override]
pandas/core/arrays/period.py:277: error: Incompatible return value type (got "signedinteger[_64Bit]", expected "int")  [return-value]
pandas/core/arrays/period.py:280: error: Incompatible return value type (got "signedinteger[_64Bit]", expected "int")  [return-value]