core-bundle/src/DataContainer/PaletteManipulator.php
public function addLegend(string $name, $parent, string $position = self::POSITION_AFTER, $hide = false): self
    {
        $this->validatePosition($position);

        $this->legends[] = [
            'name' => $name,
            'parents' => (array) $parent,
            'position' => $position,
            'hide' => (bool) $hide,
        ];

        return $this;
    }
public function addLegend(string $name, $parent, string $position = self::POSITION_AFTER, $hide = false): self
    {
        $this->validatePosition($position);

        $this->legends[] = [
            'name' => $name,
            'parents' => (array) $parent,
            'position' => $position,
            'hide' => (bool) $hide,
        ];

        return $this;
    }
If the legend already exists, nothing will be changed.

@param string|array $parent
@param bool         $hide