code: public List<ImpersonationToken> getImpersonationTokens(Object userIdOrUsername, ImpersonationState state) throws GitLabApiException {
          GitLabApiForm formData = new GitLabApiForm()
                  .withParam("state", state)
                  .withParam(PER_PAGE_PARAM, getDefaultPerPage());
          Response response = get(Response.Status.OK, formData.asMap(), "users", getUserIdOrUsername(userIdOrUsername), "impersonation_tokens");
          return (response.readEntity(new GenericType<List<ImpersonationToken>>() {}));
      }
docs: Get a list of a specified user's impersonation tokens.  Available only for admin users.
  
  <pre><code>GitLab Endpoint: GET /users/:id/impersonation_tokens</code></pre>
  
  @param userIdOrUsername the user in the form of an Integer(ID), String(username), or User instance
  @param state  the state of impersonation tokens to list (ALL, ACTIVE, INACTIVE)
  @return a list of a specified user's impersonation tokens
  @throws GitLabApiException if any exception occurs