Python bubble sort interface using C module

pyc_bubblesort.py

static PyObject *python_bubblesort(PyObject *module, PyObject *arg)
{
  assert(arg);
  Py_INCREF(arg);

  if (!PyList_CheckExact(arg))
  {
    PyErr_SetString(PyExc_ValueError, "Argument is not a list.");
    goto except;
  }
  Py_ssize_t n = PyList_Size(arg);
  if (n <= 1)
  {
    Py_DECREF(arg);
    return arg;
  }

  int isSorted = 0;
  int count = 0;
  long long *arr = (long long *)malloc(sizeof(long long) * n);

  for (size_t i = 0; i < n; i++)
  {
    PyObject *value = PyList_GetItem(arg, i);
    arr[i] = PyLong_AsLongLong(value);
  }

  while (isSorted == 0)
  {
    isSorted = 1;
    for (size_t i = 0; i < n - 1 - count; i++)
    {
      if (arr[i] > arr[i + 1])
      {
        long long temp = arr[i];
        arr[i] = arr[i + 1];
        arr[i + 1] = temp;
        isSorted = 0;
      }
    }
    count++;
  }
  PyObject *ret = PyList_New(n);
  for (size_t i = 0; i != n; ++i)
  {
    PyList_SetItem(ret, i, PyLong_FromLongLong(arr[i]));
  }
  // ret = Py_BuildValue("(o)", &arr);

  assert(!PyErr_Occurred());
  assert(ret);
  goto finally;
except:
  Py_XDECREF(ret);
  ret = NULL;
  free(arr);
finally:
  // Py_DECREF(result);
  Py_DECREF(arg);
  free(arr);
  return ret;
}