Set a value or create a named section.
+
+When invoked with three arguments <code>config</code>, <code>sectionname</code>, <code>sectiontype</code>,
+then a named section of the given type is created.
+
+When invoked with four arguments <code>config</code>, <code>sectionname</code>, <code>optionname</code> and
+<code>optionvalue</code> then the value of the specified option is set to the given value.
</li>
<li>
- value: UCI value or nil if you want to create a section
+ value: UCI value or nothing if you want to create a section
</li>
</ul>