original_string: public function getChangedData($field = null)
      {
          if ($field) {
              return isset($this->changedData[$field]) ? $this->changedData[$field] : null;
          }
          return $this->changedData;
      }
code: public function getChangedData($field = null)
      {
          if ($field) {
              return isset($this->changedData[$field]) ? $this->changedData[$field] : null;
          }
          return $this->changedData;
      }
code_tokens: public function getChangedData ( $ field = null ) { if ( $ field ) { return isset ( $ this -> changedData [ $ field ] ) ? $ this -> changedData [ $ field ] : null ; } return $ this -> changedData ; }
docstring: Return the field data before changed
  
  @param string $field
  @return string|array
docstring_tokens: Return the field data before changed