lass="even">
<td align="left">isKey</td>
<td align="left">Check if the variable is a key</td>
</tr>
<tr class="odd">
<td align="left">isSingular</td>
<td align="left">Check if the variable contains only a single value</td>
</tr>
<tr class="even">
<td align="left">isSupported</td>
<td align="left">Check if the variable class is supported by dataMaid.</td>
</tr>
</tbody>
</table>
<table style="width:40%;">
<colgroup>
<col width="40%" />
</colgroup>
<thead>
<tr class="header">
<th align="left">classes</th>
</t