Is this the correct way to check for sudo access?

has_sudo() {
  if [[ "$EUID" = 0 ]]; then
      exit 0
  else
      sudo -k # make sure to ask for password on next sudo
      if sudo true; then
          exit 0
      else
          exit 1
      fi
  fi
}

load_zshenv_on_startup() {
  if has_sudo; then
    append_zshenv_to_global_files
  else
    link_zshenv_to_home_directory
  fi
}