setBase($base); $this->setSuperscript($superscript); } public function getBase(): AbstractElement { return $this->base; } public function getSuperscript(): AbstractElement { return $this->superscript; } public function setBase(AbstractElement $element): self { $this->base = $element; return $this; } public function setSuperscript(AbstractElement $element): self { $this->superscript = $element; return $this; } }