static PyObject* test(PyObject* self, PyObject* args) {
    PyArrayObject *symbol_series_obj;
    npy_intp i=0, j=0, k=0;
    if (!PyArg_ParseTuple(args, "O!ll|l",
                &PyArray_Type, &symbol_series_obj,
                &i, &j, &k)
    ) return NULL;

    if (NULL == symbol_series_obj)  return NULL;

    // get number of dimensions:
    npy_intp num_dims = PyArray_NDIM(symbol_series_obj);

    // help-vars
    int typenum = NPY_DOUBLE;
    PyArray_Descr *descr = PyArray_DescrFromType(typenum);
    npy_intp dims[4];

    // incref, as PyArray_AsCArray steals reference
    Py_INCREF(symbol_series_obj);

    // is 2D-array
    if (num_dims == 2){
        double **symbol_series;
        if (PyArray_AsCArray((PyObject **) &symbol_series_obj,
                    (void **) &symbol_series, dims, 2, descr) < 0){
            PyErr_SetString(PyExc_TypeError, "error converting to c array");
            return NULL;}
        printf("2D-array[%i][%i]: %.2f\n",
                (int) i, (int) j, symbol_series[i][j]);
        // free C-like array
        PyArray_Free((PyObject *) symbol_series_obj, (void *) symbol_series);
    }

    // is 3D-array
    else if (num_dims == 3){
        double ***symbol_series;
        if (PyArray_AsCArray((PyObject **) &symbol_series_obj,
                    (void ***) &symbol_series, dims, 3, descr) < 0){
            PyErr_SetString(PyExc_TypeError, "error converting to c array");
            return NULL;}
        printf("3D-array[%i][%i][%i]: %.2f\n",
                (int) i, (int) j, (int) k, symbol_series[i][j][k]);
        // free C-like array
        PyArray_Free((PyObject *) symbol_series_obj, (void *) symbol_series);
    }
    else {
        printf("error not 2D or 3D");
        return NULL;
    }

    Py_RETURN_NONE;
}

import numpy as np
from my_module import test

def get_random_item(arr):
    "selects a random item from given array with numpy and c-ext"
    # get coord:
    cords = tuple([np.random.randint(dim) for dim in arr.shape])
    str_cords = ''.join(("[{}]".format(cord) for cord in cords))

    # numpy:
    print("numpy: arr{} = {}".format(str_cords, arr[cords]))

    # c-version:
    test(arr, *cords)


if __name__ == '__main__':
    ARR2D = np.arange(0, 0.27, 0.01).reshape(3, 9)
    for _ in range(10):
        get_random_item(ARR2D)

    ARR3D = np.arange(0, 0.27, 0.01).reshape(3, 3, 3)
    for _ in range(10):
        get_random_item(ARR3D)