title: Copy type signature from another function
body: <p>Imagine I have a set of functions like below. <code>foo</code> has a lot of arguments of various types, and <code>bar</code> passes all its arguments to that other function. Is there any way to make mypy understand that <code>bar</code> has the same type as <code>foo</code> without explicitly copying the whole argument list?</p>
  
  <pre class="lang-py prettyprint-override"><code>def foo(a: int, b: float, c: str, d: bool, *e: str, f: str = "a", g: str = "b") -&gt; str:
      ...
  
  def bar(*args, **kwargs):
      val = foo(*args, **kwargs)
      ...
      return val
  </code></pre>