PY_TYPE_CHECK

%cython from sage.all import Integer cpdef t1(x): cdef bint a for i in range(1000): a=PY_TYPE_CHECK(x,Integer) return a cpdef t2(x): cdef bint a for i in range(1000): a=isinstance(x,Integer) return a 

timeit('t1(1)') 

625 loops, best of 3: 24 µs per loop

625 loops, best of 3: 24 µs per loop

timeit('t2(1)') 

625 loops, best of 3: 35 µs per loop

625 loops, best of 3: 35 µs per loop

timeit('t1(int(1))') 

625 loops, best of 3: 43.3 µs per loop

625 loops, best of 3: 43.3 µs per loop

timeit('t2(int(1))') 

625 loops, best of 3: 174 µs per loop

625 loops, best of 3: 174 µs per loop

t1(int(1)) 

True

True

t2(int(1)) 

True

True