title: Why is imperative mood important for docstrings?
body: <p>The error code D401 for pydocstyle reads: <code>First line should be in imperative mood</code>.</p>
  
  <p>I often run into cases where I write a docstring, have this error thrown by my linter, and rewrite it -- but the two docstrings are semantically identical. Why is it important to have imperative mood for docstrings?</p>