>>> def test(pod=42, /, pk): ...
  File "<stdin>", line 1
    def test(pod=42, /, pk): ...
                        ^^
SyntaxError: parameter without a default follows parameter with a default

>>> lambda pod=42, /, pk: ...
  File "<stdin>", line 1
    lambda pod=42, /, pk: ...
                      ^^
SyntaxError: parameter without a default follows parameter with a default

>>> import inspect
>>> def one(pk): ...
... 
>>> def two(pod=42, /): ...
... 
>>> sig1 = inspect.signature(one)
>>> sig2 = inspect.signature(two)
>>> inspect.Signature((sig2.parameters['pod'], sig1.parameters['pk']))
<Signature (pod=42, /, pk)>

Traceback (most recent call last):
  File "/Users/sobolev/Desktop/cpython/ex.py", line 7, in <module>
    print(inspect.Signature((sig2.parameters['pod'], sig1.parameters['pk'])))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/sobolev/Desktop/cpython/Lib/inspect.py", line 3039, in __init__
    raise ValueError(msg)
ValueError: non-default argument follows default argument