Pybind11:在C++中使用Pybind11转换numpy数组的问题

我正试图从C++中获得一个Python数组，并将其放回Python函数中，同时使用带有Pybind11的C++。首先，我访问一个numpy数组的字典，然后将每个numpy数组放入一个Python函数中，该函数只计算数组中元素的总和。给我带来麻烦的代码的主要部分是：

py::array item = list_items.attr("__getitem__")(i); 
//equivalent to dict.__getitem__[i]
//code runs if removing the following line
boost_mod.attr("sum_of_dict")(item).cast<int>(); 
//calls the function sum_of_dict in the module boost_mod having as argument a 1D numpy array
//this function computes the sum of the elements in the numpy array, which are all integers 

我想我有一个转换问题，我不知道如何克服它。我看过这个文档链接，但它没有帮助。我还研究了不同的cast可能性，以及其他类似于这篇或另一篇的帖子，但它们不适用于我的问题，因为它们不使用pybind。对于转换和使用numpy数组对象的任何帮助或提示，我们将不胜感激。非常感谢

完整代码如下：

C++代码

#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include <chrono>
#include <thread>
#include <Python.h>
namespace py = pybind11;
py::module boost_mod = py::module::import("boost_mod");
int parallelize(py::dict list_items, py::object q_in, py::object q_out){
unsigned int sum = 0;
unsigned int len = list_items.attr("__len__")().cast<int>();
for( unsigned int i = 0; i < len ; i++){
//PROBLEM IS HERE//
py::array item = list_items.attr("__getitem__")(i);
sum+= boost_mod.attr("sum_of_dict")(item).cast<int>();
std::this_thread::sleep_for(std::chrono::milliseconds(5));
}
return sum;
}
PYBIND11_MODULE(cpp_parallel, m) {
m.doc() = "pybind11 plugin";
m.def("parallelize", &parallelize,
"a function");
}

Python模块，包含函数

import numpy as np
import cpp_parallel as cpp
class child(object):
def __init__(self, index):
self.nb = index
self.total = None
def sum(self, i, j):
return self.nb + self.nb
def create_dict(self):
self.list_items = {}
for i in range(self.nb):
lth = np.random.randint(1,10)
a = np.random.binomial(size=lth, n=1, p =0.6)
self.list_items[i] = a
return self.list_items
def sum_of_dict(self, element):  # fonction comme eval function
a = np.sum(element)
return a
def sub(self, q_in, q_out):
//FUNCTION CALLED FROM C++//
return cpp.parallelize(self.list_items, q_in, q_out)

Python代码

from multiprocessing import Process, Queue
import time
import boost_mod as test
import cpp_parallel as cpp
q_in = Queue()
q_out = Queue()
q_in.put(True)
dict_evaluated = test.child(1000)
dict_evaluated.create_dict()
dict_evaluated.sub(q_in, q_out)