Some functions can be described by the single signature. See examples in msg285647. Selected examples:

  dict.pop(key)
  dict.pop(key, default)

  type(obj)
  type(name, bases, mapping)

  range(stop)
  range(start, stop, step=1)

  min(iterable, *, key=identity)
  min(iterable, *, default, key=identity)
  min(*args, key=identity)

I think the only way to resolve this problem is to add the support of multiple signatures in inspect, pydoc, Argument Clinic, etc.