def METHOD_NAME(iam, name=None):
    """Retrieve the attributes of a server certificate if it exists or all certs.
    Args:
        iam (botocore.client.IAM): The boto3 iam instance.
    Kwargs:
        name (str): The name of the server certificate.
    Basic Usage:
        >>> import boto3
        >>> iam = boto3.client('iam')
        >>> name = "server-cert-name"
        >>> results = get_server_certs(iam, name)
        {
            "upload_date": "2015-04-25T00:36:40+00:00",
            "server_certificate_id": "ADWAJXWTZAXIPIMQHMJPO",
            "certificate_body": "-----BEGIN CERTIFICATE-----\nbunch of random data\n-----END CERTIFICATE-----",
            "server_certificate_name": "server-cert-name",
            "expiration": "2017-06-15T12:00:00+00:00",
            "path": "/",
            "arn": "arn:aws:iam::123456789012:server-certificate/server-cert-name"
        }
    """
    results = dict()
    try:
        if name:
            server_certs = [iam.get_server_certificate(ServerCertificateName=name)["ServerCertificate"]]
        else:
            server_certs = iam.list_server_certificates()["ServerCertificateMetadataList"]
        for server_cert in server_certs:
            if not name:
                server_cert = iam.get_server_certificate(ServerCertificateName=server_cert["ServerCertificateName"])[
                    "ServerCertificate"
                ]
            cert_md = server_cert["ServerCertificateMetadata"]
            results[cert_md["ServerCertificateName"]] = {
                "certificate_body": server_cert["CertificateBody"],
                "server_certificate_id": cert_md["ServerCertificateId"],
                "server_certificate_name": cert_md["ServerCertificateName"],
                "arn": cert_md["Arn"],
                "path": cert_md["Path"],
                "expiration": cert_md["Expiration"].isoformat(),
                "upload_date": cert_md["UploadDate"].isoformat(),
            }
    except botocore.exceptions.ClientError:
        pass
    return results