human
Solve the following python programming problem given the following code:
def start(self, callback, sig_num) : 
    'Start the signal listener

        :type callback: Callable(sig_handle: Signal, sig_num: int)
        :type sig_num: int
        ' 
    def cb_wrapper(uv_signal_t, signum) : 
        callback (self, signum) 
ffi_cb = ffi.callback ('void (*)(uv_signal_t *, int)', ffi_cb) 
    self._ffi_cb = ffi_cb 
    libuv.uv_signal_start (self.handle, ffi_cb, sig_num) 

    
    

    Fix the buggy line: ffi_cb = ffi.callback ('void (*)(uv_signal_t *, int)', ffi_cb)
assistant
#Here is Python program to fix the buggy line: ffi_cb = ffi.

ffi_cb = ffi.callback ('void (*)(uv_signal_t *, int)', def cb_wrapper()