code: public Optional<Commit> getOptionalMergeBase(Object projectIdOrPath, List<String> refs) throws GitLabApiException {
          try {
              return (Optional.ofNullable(getMergeBase(projectIdOrPath, refs)));
          } catch (GitLabApiException glae) {
              return (GitLabApi.createOptionalFromException(glae));
          }
      }
docs: Get an Optional instance with the value of the common ancestor
  for 2 or more refs (commit SHAs, branch names or tags).
  
  <pre><code>GitLab Endpoint: GET /projects/:id/repository/merge_base</code></pre>
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance
  @param refs a List of 2 or more refs (commit SHAs, branch names or tags)
  @return an Optional instance with the Commit instance containing the common ancestor as the value
  @throws GitLabApiException if any exception occurs