code: public function add(self $b)
      {
          $this->_checkVectorSpace($b);
  
          $bComponents = $b->components();
          $sum = [];
          foreach ($this->components() as $i => $component) {
              $sum[$i] = $component + $bComponents[$i];
          }
  
          return new static($sum);
      }
docs: Adds two vectors together.
  
  @api
  @param self $b The vector to add.
  @return self The sum of the two vectors.
  @throws Exception if the vectors are not in the same vector space.
  @see self::_checkVectorSpace() For exception information.