title: Type hinting / annotation (PEP 484) for numpy.ndarray
body: <p>Has anyone implemented type hinting for the specific <a href="http://docs.scipy.org/doc/numpy/reference/arrays.ndarray.html" rel="noreferrer"><code>numpy.ndarray</code></a> class?</p>
  <p>Right now, I'm using <a href="https://docs.python.org/3/library/typing.html#the-any-type" rel="noreferrer"><code>typing.Any</code></a>, but it would be nice to have something more specific.</p>
  <p>For instance if the NumPy people added a <a href="https://docs.python.org/3/library/typing.html#type-aliases" rel="noreferrer">type alias</a> for their <a href="http://docs.scipy.org/doc/numpy/user/basics.creation.html#converting-python-array-like-objects-to-numpy-arrays" rel="noreferrer">array_like</a> object class. Better yet, implement support at the <a href="http://docs.scipy.org/doc/numpy/reference/arrays.dtypes.html" rel="noreferrer">dtype</a> level, so that other objects would be supported, as well as <a href="http://docs.scipy.org/doc/numpy/reference/ufuncs.html" rel="noreferrer">ufunc</a>.</p>