original_string: public function union(): self
      {
          $query = new self;
          $query->clauses = $this->clauses->add(
              new Clause\UnionClause
          );
  
          return $query;
      }
code: public function union(): self
      {
          $query = new self;
          $query->clauses = $this->clauses->add(
              new Clause\UnionClause
          );
  
          return $query;
      }
code_tokens: public function union ( ) : self { $ query = new self ; $ query -> clauses = $ this -> clauses -> add ( new Clause \ UnionClause ) ; return $ query ; }
docstring: Add a UNION clause
  
  @return self
docstring_tokens: Add a UNION clause