title: What is the meaning of a forward slash "/" in a Python method signature, as shown by help(foo)?
body: <p>In the signature returned interactively by <code>help(foo)</code>, what is the meaning of a <code>/</code>?</p>
  
  <pre><code>In [37]: help(object.__eq__)
  
  Help on wrapper_descriptor:
  
  __eq__(self, value, /)
      Return self==value.
  
  In [55]: help(object.__init__)
  
  Help on wrapper_descriptor:
  
  __init__(self, /, *args, **kwargs)
      Initialize self.  See help(type(self)) for accurate signature.
  </code></pre>
  
  <p>I thought it might be related to keyword-only arguments, but it's not.  When I create my own function with keyword-only arguments, positional and keyword-only arguments are separated by <code>*</code> (as expected), not by <code>/</code>.  What does the <code>/</code> mean?</p>