@Override
    @CanIgnoreReturnValue
    public AttributeDefinitionStore registerAttributeDefinition(final String key, final AttributeDefinition definition) {
        LOGGER.trace("Registering attribute definition [{}] by key [{}]", definition, key);
        val keyToUse = getAttributeDefinitionKey(key, definition);
        attributeDefinitions.put(keyToUse, definition);
        return this;
    }
Register attribute definitions.

@param entries the entries
core/cas-server-core-authentication-api/src/main/java/org/apereo/cas/authentication/attribute/DefaultAttributeDefinitionStore.java