tr>
</thead>
<tbody>
<tr class="odd">
<td>idx</td>
<td>pd.Series or pd.DatetimeIndex</td>
<td>The <code>idx</code> parameter is a pandas Series or pandas DatetimeIndex object that contains datetime values. It represents the dates that you want to round down.</td>
<td><em>required</em></td>
</tr>
<tr class="even">
<td>unit</td>
<td>str</td>
<td>The <code>unit</code> parameter in the <code>ceil_date</code> function is a string that specifies the time unit to which the dates in the <code>idx</code> series shou