Wrapping custom type C++ pointer in Cython

What is the best way to wrap a custom type C++ pointer using Cython?

For example:

import numpy as np
cimport numpy as np

cdef extern from "A_c.h"
    cdef cppclass A:
       A();
       void Foo(A* vec);

cdef class pyA:
    cdef A *thisptr
    def ___cinit___(self):
        self.thisptr = new A()
    def __dealloc___(self):
        del self.thisptr

How should I use cython to wrap Foo? I have tried the following but I have gotten assertion errors from Buffer.py or the error that A is not a base type of memoryview slice

def Foo(self, np.ndarray[A, mode='c'] vec)
def Foo(self, A[::1] vec)