Python function keyword-only and positional-only

def function(positional_only, /, flexible, *, keyword_only):
    pass

def connect(*, host: str, port: int):
    pass
connect(host="localhost", port=8080)  # ✓
connect("localhost", 8080)            # ✗

def pow(x, y, /):
    return x ** y
pow(2, 3)      # ✓
pow(x=2, y=3)  # ✗

def process(a, /, b, *, c):
    pass
process(1, 2, c=3)      # ✓
process(1, b=2, c=3)    # ✓
process(a=1, b=2, c=3)  # ✗ a는 위치 전용
process(1, 2, 3)        # ✗ c는 키워드 전용