original_string: public function validate_sequence_number($slot, $postdata = null) {
          $qa = $this->get_question_attempt($slot);
          $sequencecheck = $qa->get_submitted_var(
                  $qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
          if (is_null($sequencecheck)) {
              return false;
          } else if ($sequencecheck != $qa->get_sequence_check_count()) {
              throw new question_out_of_sequence_exception($this->id, $slot, $postdata);
          } else {
              return true;
          }
      }
code: public function validate_sequence_number($slot, $postdata = null) {
          $qa = $this->get_question_attempt($slot);
          $sequencecheck = $qa->get_submitted_var(
                  $qa->get_control_field_name('sequencecheck'), PARAM_INT, $postdata);
          if (is_null($sequencecheck)) {
              return false;
          } else if ($sequencecheck != $qa->get_sequence_check_count()) {
              throw new question_out_of_sequence_exception($this->id, $slot, $postdata);
          } else {
              return true;
          }
      }
code_tokens: public function validate_sequence_number ( $ slot , $ postdata = null ) { $ qa = $ this -> get_question_attempt ( $ slot ) ; $ sequencecheck = $ qa -> get_submitted_var ( $ qa -> get_control_field_name ( 'sequencecheck' ) , PARAM_INT , $ postdata ) ; if ( is_null ( $ sequencecheck ) ) { return false ; } else if ( $ sequencecheck != $ qa -> get_sequence_check_count ( ) ) { throw new question_out_of_sequence_exception ( $ this -> id , $ slot , $ postdata ) ; } else { return true ; } }
docstring: Check that the sequence number, that detects weird things like the student
  clicking back, is OK. If the sequence check variable is not present, returns
  false. If the check variable is present and correct, returns true. If the
  variable is present and wrong, throws an exception.
  @param int $slot the number used to identify this question within this usage.
  @param array $submitteddata the submitted data that constitutes the action.
  @return bool true if the check variable is present and correct. False if it
  is missing. (Throws an exception if the check fails.)
docstring_tokens: Check that the sequence number that detects weird things like the student clicking back is OK . If the sequence check variable is not present returns false . If the check variable is present and correct returns true . If the variable is present and wrong throws an exception .