Why can a function run normally without parameters？

[Yes-Jumby]

I am confused that Why can a function run normally without parameters，anyone help？Thanks
pctx.push() from here in test_driver.py:

    def test_additional_primary_context(self):
        if drv.get_version() < (2, 0, 0):
            return
        if drv.get_version() >= (2, 2, 0) and drv.get_version() < (8,):
            if drv.Context.get_device().compute_mode == drv.compute_mode.EXCLUSIVE:
                return

        mem_a = drv.mem_alloc(50)
        pctx = drv.Context.get_device().retain_primary_context()
        **pctx.push()**
        mem_b = drv.mem_alloc(60)

        del mem_a
        del mem_b
        pctx.detach()

I dive in c++-python-interface:

  // {{{ context
  {
    typedef context cl;
    py::class_<cl, shared_ptr<cl>, boost::noncopyable >("Context", py::no_init)
      **.def("push", context_push)**

in c++:

  inline
  void context_push(boost::shared_ptr<context> ctx)
  {
    context::prepare_context_switch();
    CUDAPP_CALL_GUARDED(cuCtxPushCurrent, (ctx->m_context));
    context_stack::get().push(ctx);
    ++ctx->m_use_count;
  }

[inducer]

I'm not sure I understand the question. What behavior did you observe? What would you like to happen instead?

[Yes-Jumby]

I'm not sure I understand the question. What behavior did you observe? What would you like to happen instead?

It should be a error for parameter miss,but it could work(i had tried it,and it works successful).
I can't find where the default parameters were given to the function in python warp,could you help me?

[inducer]

What parameter is missing, in your opinion? You highlight Context.push; that's documented to not have parameters:

https://documen.tician.de/pycuda/driver.html#pycuda.driver.Context.push