original_string: public function multiple(): self
      {
          $unique_array = array_unique($this->getArrayCopy());
          return new ArrayMap(array_diff_assoc($this->getArrayCopy(), $unique_array));
      }
code: public function multiple(): self
      {
          $unique_array = array_unique($this->getArrayCopy());
          return new ArrayMap(array_diff_assoc($this->getArrayCopy(), $unique_array));
      }
code_tokens: public function multiple ( ) : self { $ unique_array = array_unique ( $ this -> getArrayCopy ( ) ) ; return new ArrayMap ( array_diff_assoc ( $ this -> getArrayCopy ( ) , $ unique_array ) ) ; }
docstring: Get duplicate values in an array
  @return $this
docstring_tokens: Get duplicate values in an array