title: Can mypy check docstrings?
body: <p>I have <a href="https://numpydoc.readthedocs.io/en/latest/format.html" rel="noreferrer">numpydoc-style docstrings</a>:</p>
  
  <pre><code>def foobar(filename, copy, dtype, iterable, shape, files):
      """
      foobar is 42.
  
      Parameters
      ----------
      filename : str
      copy : bool
      dtype : data-type
      iterable : iterable object
      shape : int or tuple of int
      files : list of str
  
      Returns
      -------
      foobarfoo : int
      """
      pass
  </code></pre>
  
  <p><strong>Is it possible to check if the docstring-types can possibly be correct?</strong></p>
  
  <p>(side question: Can numpy return/print the function signatures it discovered?)</p>
  
  <p>For example, I would expect the following to fail:</p>
  
  <h2>Return Types</h2>
  
  <pre><code>def foobar():
      """
      Returns
      -------
      blub : int
      """
      return "foo"
  </code></pre>
  
  <p>or</p>
  
  <pre><code>def foobar(a, b):
      """
      Parameters
      ----------
      a : number
      b : number
  
      Returns
      -------
      blub : int
      """
      if a &gt; b:
          return "foo"
      return 42
  </code></pre>
  
  <h2>Parameter types</h2>
  
  <pre><code>def foobar(a, b):
      """
      Parameters
      ----------
      a : str
      b : int
  
      Returns
      -------
      blub : int
      """
      return a * b
  </code></pre>