code: public function issuesBySeverity(Issue\IssueSeverity $severity)
      {
          $this->typeCheck->issuesBySeverity(func_get_args());
  
          $issues = array();
          foreach ($this->issues() as $issue) {
              if ($issue->severity() === $severity) {
                  $issues[] = $issue;
              }
          }
  
          return $issues;
      }
docs: @param Issue\IssueSeverity $severity
  
  @return array<Issue\IssueInterface>