chobie\Jira\Issue::get PHP Method

    public function get($field_key)
    {
        if (isset($this->fields[$field_key])) {
            return $this->fields[$field_key];
        }
        return null;
    }

 /**
  * Determines if link is accepted.
  *
  * @param Issue $issue        Issue.
  * @param Issue $linked_issue Linked issue.
  *
  * @return boolean
  */
 protected function isLinkAccepted(Issue $issue, Issue $linked_issue)
 {
     $issue_type = $linked_issue->get('issuetype');
     return $issue_type['id'] === $this->getChangelogEntryIssueTypeId();
 }