code: public DeployKey addDeployKey(Object projectIdOrPath, String title, String key, Boolean canPush) throws GitLabApiException {
  
          GitLabApiForm formData = new GitLabApiForm()
                  .withParam("title", title, true)
                  .withParam("key", key, true)
                  .withParam("can_push",  canPush);
          Response response = post(Response.Status.CREATED, formData,
                  "projects", getProjectIdOrPath(projectIdOrPath), "deploy_keys");
          return (response.readEntity(DeployKey.class));
      }
docs: Creates a new deploy key for a project.
  
  <pre><code>GitLab Endpoint: POST /projects/:id/deploy_keys</code></pre>
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance
  @param title the new deploy key's title, required
  @param key the new deploy key, required
  @param canPush can deploy key push to the project's repository, optional
  @return an DeployKey instance with info on the added deploy key
  @throws GitLabApiException if any exception occurs