lib/MultiIniModifier.php
public function setValueOnMaster($name, $value, $section = 0, $key = null)
    {
        if (!$this->master instanceof IniModifierInterface) {
            throw new IniException('Cannot set value on master which is only an ini reader');
        }
        $this->master->setValue($name, $value, $section, $key);
    }
public function setValueOnMaster($name, $value, $section = 0, $key = null)
    {
        if (!$this->master instanceof IniModifierInterface) {
            throw new IniException('Cannot set value on master which is only an ini reader');
        }
        $this->master->setValue($name, $value, $section, $key);
    }
modify an option in the master ini file. If the option doesn't exist,
it is created.

@param string $name    the name of the option to modify
@param string $value   the new value
@param string $section the section where to set the item. 0 is the global section
@param string $key     for option which is an item of array, the key in the array