def delete_external_identifier(options={})
      return OpenStruct.new(body: { "errors" => [{ "title" => "ORCID access token missing" }] }) unless orcid_token.present?
      return OpenStruct.new(body: { "errors" => [{ "title" => "Put code missing" }] }) unless put_code.present?

      orcid_api_url = options[:sandbox] ? 'https://api.sandbox.orcid.org' : 'https://api.orcid.org'