Add custom tabs to the MemberPress Account Page

mp_custom_account_nav.php

<?php
add_action('mepr_account_nav', 'custom_account_nav', 10, 1);
function custom_account_nav($user) {
  $mepr_options = MeprOptions::fetch();
  $whaa_url = $mepr_options->account_page_url('action=whaa');

?>
  <span class="mepr-nav-item custom-whaa">
    <a href="<?php echo $whaa_url; ?>" id="mepr-account-whaa"><?php _e('Whaa', 'memberpress'); ?></a>
  </span>
<?php
}

add_action('mepr_account_nav_content', 'custom_account_nav_content', 10, 1);
function custom_account_nav_content( $action ) {
  if($action == 'whaa') {
    echo "Boo Yah!";
  }
}