title: Python np.busday_count with datetime64[ns] as input
body: <p>I have a column from a pandas Dataframe that I want to use as input for <code>np.busday_count</code>: </p>
  
  <pre><code>np.busday_count(df['date_from'].tolist(), df['date_to_plus_one'].tolist(), weekmask='1000000')
  </code></pre>
  
  <p>I have always use <code>.tolist()</code> but since one of the last updates this results in an error:</p>
  
  <pre><code>&gt; TypeError: Iterator operand 0 dtype could not be cast from
  &gt; dtype('&lt;M8[us]') to dtype('&lt;M8[D]') according to the rule 'safe'
  </code></pre>
  
  <p>The column <code>df['date_from']</code>is of type <code>dtype: datetime64[ns]</code>.</p>
  
  <p>Any tips or solution for this?</p>