src/Metable/Attribute.php
protected function set($key, $value, $group = 'default')
    {
        $this->setMetaKey($key);
        $this->setValue($value);
        $this->setMetaGroup($group);
    }
protected function set($key, $value, $group = 'default')
    {
        $this->setMetaKey($key);
        $this->setValue($value);
        $this->setMetaGroup($group);
    }
Set the meta attribute.

@param string $key
@param mixed  $value
@param string $group