How to pass void pointer (starting of an array) to C function from Cython?

Question

I have a C function in write.h:

int write(int fd, void* arr, int size);

I have written write.pxd file to define it in Cython:

cdef extern from "write.h":
  int write(int fd, void* arr, int size)

Now, how do I write the write.pyx for its implementation. I tried this:

def write(int fd, void* buf, int size):
  return write(fd, buf, size)

But it complains that:

Cannot convert Python object argument to type 'void *'

How should I define so that I can send a list from Python and C gets the starting address of that list. For example, I want to call:

my_list = [1, 2, 3]
write(fd, my_list, 3 * 4)

as sizeof(int) is 4.