# Pastebin SYmOPqOW
(pypy37) dev@brick:/tmp$ python x.py 
b'+'
(pypy37) dev@brick:/tmp$ python x.py 
b'\x13'
(pypy37) dev@brick:/tmp$ cat x.py 

from cffi import FFI

ffi = FFI()
l = [None]
with ffi.new("char[]", 1024) as x:
    x[3] = b'\x13'
    l[-1] = x
import gc
gc.collect()
gc.collect()
x = ffi.new("char[]", 1024)
print(l[0][3])
(pypy37) dev@brick:/tmp$