Missing config for "Signature AuthnRequest"

here the doc that need an integration Link[https://docs.gitlab.com/ee/integration/saml.html]

Here the example for Signature AuthRequest

{
        name: 'saml',
        args: {
            assertion_consumer_service_url: 'https://mywebsite/users/auth/saml/callback',
            assertion_consumer_service_binding: 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
            idp_cert_fingerprint: '77:EE:EE:AA:67:FA:78:4C:E2:ED:E8:57:AC:EE:AC:AB:AA:FF:FD:FD',
            idp_sso_target_url: 'https://idp.url/auth/SSOPOST/metaAlias/ent/providerIDP',
            idp_sso_target_binding: 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
            idp_slo_target_url: 'https://idp.url/auth/IDPSloPOST/metaAlias/ent/providerIDP',
            idp_slo_target_binding: 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
            sso_binding: 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
            protocol_binding: 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
            issuer: 'sp_gitlab',
            name_identifier_format: 'urn:oasis:names:tc:SAML:2.0:nameid-format:persistent',
            ##### Begin ------- Signature AuthnRequest ######
            certificate: "-----BEGIN CERTIFICATE-----
MIIDzjCCArYCCQCxUOzAVm5w3DANBgkqhkiG9w0BAQUFADCBqDELMAkGA1UEBhMC
....
v84ULsyAgv8sVJ4XerZ9wr7B
-----END CERTIFICATE-----",
            private_key: "-----BEGIN RSA PRIVATE KEY-----
MIIEpQIBAAKCAQEAxcTsJ0sBMAH9NwEvDT5qcGBA6JiChtM90I9di7YC98lO5qFM
....
lfIj9QAaFdL9lPskg6zX6HEooOEoLib8fm9IZCIChjhsdjoj/6QXP6k=
-----END RSA PRIVATE KEY-----",
            security: {
                authn_requests_signed: true,
                embed_sign: true,
                digest_method: "XMLSecurity::Document::SHA1",
                signature_method: "http://www.w3.org/2000/09/xmldsig#rsa-sha1"
            }
            ##### End ------- Signature AuthnRequest ######
        },
        label: 'SAML Auth'
    }