Sokil\Mongo\Expression::merge PHP Method

    public function merge(Expression $expression)
    {
        $this->_expression = array_merge_recursive($this->_expression, $expression->toArray());
        return $this;
    }

 /**
  * Merge expression
  * @param \Sokil\Mongo\Expression $expression
  * @return \Sokil\Mongo\Cursor
  */
 public function query(Expression $expression)
 {
     $this->expression->merge($expression);
     return $this;
 }