title: Debugging Numpy VisibleDeprecationWarning (ndarray from ragged nested sequences)
body: <p>Since NumPy version 19.0, one must specify <code>dtype=object</code> when creating an array from &quot;ragged&quot; sequences. I'm faced with a large number of array calls from my own code and Pandas using threading, line-by-line debugging led me nowhere.</p>
  <p>I'd like to figure out which call resulted in <em>VisibleDeprecationWarning</em> in my own code or a call from Pandas. How would I be able to debug this? I've been looking through the source and I cannot see this warning getting called in Python (only in numpy.core._multiarray_umath.cp38-win_amd64.pyd).</p>