from cpython.datetime cimport datetime from numpy cimport int64_t cdef int64_t NPY_NAT cdef set c_nat_strings cdef class _NaT(datetime): cdef readonly: int64_t _value cdef _NaT c_NaT cdef bint checknull_with_nat(object val) cdef bint is_dt64nat(object val) cdef bint is_td64nat(object val)