Dudo on "Can't output do_settings_sections . Can't understand why"

I've this code:

/* Hook to admin_menu the yasr_add_pages function above */
add_action('admin_menu', 'yasr_add_pages');

function yasr_add_pages() {

    //Add Settings Page
    add_options_page(
                    'Yet Another Stars Rating: Settings',               //Page Title
                    __('Yet Another Stars Rating: Settings', 'yasr'),   //Menu Title
                    'manage_options',                                   //capablity
                    'yasr_settings_page',                               //menu slug
                    'yasr_settings_page_content'                        //The function to be called to output the content for this page.
                    ); 

}

/* Settings Page Content */
function yasr_settings_page_content() {
    if ( !current_user_can( 'manage_options' ) )  {
        wp_die( __( 'You do not have sufficient permissions to access this page.', 'yasr' ) );
    }
    include (YASR_ABSOLUTE_PATH . '/yasr-settings-page.php');

} //End yasr_settings_page_content

and, this is the content in yasr-settings-page:

<div class="wrap">
    <h2>Settings API Demo</h2>
    <form action="options.php" method="post">
        <?php
            settings_fields( 'yasr_multi_form' );
            do_settings_sections( 'yasr_settings_page' );
            submit_button( 'Salva' );
        ?>
    </form>
</div>

<?php

add_action( 'admin_init', 'yasr_multi_form_init' );

function yasr_multi_form_init() {
    register_setting (
                'yasr_multi_form', // A settings group name. Must exist prior to the register_setting call. This must match the group name in settings_fields()
                'yasr_multi_form_data' //The name of an option to sanitize and save.
    );

add_settings_section( 'yasr_section_id', 'Gestione Multi Set', 'yasr_section_callback', 'yasr_settings_page' );
add_settings_field( 'yasr_field_name_id', 'Nome Set', 'yasr_nome_callback', 'yasr_settings_page', 'yasr_section_id' );
}

function yasr_section_callback() {
    echo "Descrizione sezione";
}

function yasr_nome_callback() {
    $option = get_option( 'yasr_multi_form_data' );
    $name = esc_attr( $option['name'] );
    echo "<input type='text' name='yasr_multi_form_data[name]' value='' />";
}

The settings page output settings_field function (I can see the input type hidden on my source) and the submit button, but I can't render the do_settings_section and I really can't understand why. Any suggestions?