Use custom field in cart

I have some trouble. Try get in cart custom field:

$ds=’,’.get_custom_field(‘ynamicalprice:formatted_list’, ‘, ‘).’,’;

and $ds is empty.
How can i get this field information?

I use this code in cart.php:

/**
 * Cart Page
 *
 * @author 		WooThemes
 * @package 	WooCommerce/Templates
 * @version     2.1.0
 */

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

global $woocommerce,$product,$order,$post;

wc_print_notices();

do_action( 'woocommerce_before_cart' ); ?>

<style>
.btn_yg{text-transform: uppercase;
    border: none;
    width: auto;
	padding-right:5px; padding-left:5px; padding: 6px 12px; border: 1px solid transparent;
	background:white!important; color:black!important;}

</style>

<form action="<?php echo esc_url( WC()->cart->get_cart_url() ); ?>" method="post">

<?php do_action( 'woocommerce_before_cart_table' ); ?>

<table class="shop_table cart" cellspacing="0">
	<thead>
		<tr>
			<th class="product-remove">&nbsp;</th>
			<th class="product-thumbnail">&nbsp;</th>
			<th class="product-name"><?php _e( 'Product', 'woocommerce' ); ?></th>
			<th class="product-price"><?php _e( 'Price', 'woocommerce' ); ?></th>
			<th class="product-quantity"><?php _e( 'Quantity', 'woocommerce' ); ?></th>
			<th class="product-subtotal"><?php _e( 'Total', 'woocommerce' ); ?></th>
		</tr>
	</thead>
	<tbody>
		<?php do_action( 'woocommerce_before_cart_contents' ); ?>

		<?php
		foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
			$_product     = apply_filters( 'woocommerce_cart_item_product', $cart_item['data'], $cart_item, $cart_item_key );
			$product_id   = apply_filters( 'woocommerce_cart_item_product_id', $cart_item['product_id'], $cart_item, $cart_item_key );
			$days = get_custom_field('ynamicalprice:to_array');			

			if ( $_product && $_product->exists() && $cart_item['quantity'] > 0 && apply_filters( 'woocommerce_cart_item_visible', true, $cart_item, $cart_item_key ) ) {
				?>
				<tr class="<?php echo esc_attr( apply_filters( 'woocommerce_cart_item_class', 'cart_item', $cart_item, $cart_item_key ) ); ?>">

					<td class="product-remove">
						<?php
							echo apply_filters( 'woocommerce_cart_item_remove_link', sprintf( '<a href="%s" class="remove" title="%s">&times;</a>', esc_url( WC()->cart->get_remove_url( $cart_item_key ) ), __( 'Remove this item', 'woocommerce' ) ), $cart_item_key );
						?>
					</td>

					<td class="product-thumbnail">
						<?php
							$thumbnail = apply_filters( 'woocommerce_cart_item_thumbnail', $_product->get_image(), $cart_item, $cart_item_key );

							if ( ! $_product->is_visible() )
								echo $thumbnail;
							else
								printf( '<a href="%s">%s</a>', $_product->get_permalink(), $thumbnail );
						?>
					</td>

					<td class="product-name">
						<?php							

							if ( ! $_product->is_visible() )
								echo apply_filters( 'woocommerce_cart_item_name', $_product->get_title(), $cart_item, $cart_item_key );
							else
								echo apply_filters( 'woocommerce_cart_item_name', sprintf( '<a href="%s">%s</a>', $_product->get_permalink(), $_product->get_title() ), $cart_item, $cart_item_key );

							// Meta data
							echo WC()->cart->get_item_data( $cart_item );

               				// Backorder notification
               				if ( $_product->backorders_require_notification() && $_product->is_on_backorder( $cart_item['quantity'] ) )
               					echo '<p class="backorder_notification">' . __( 'Available on backorder', 'woocommerce' ) . '</p>';

						?>
					</td>

					<td class="product-price">
						<?php
							echo apply_filters( 'woocommerce_cart_item_price', WC()->cart->get_product_price( $_product ), $cart_item, $cart_item_key );
						?>
					</td>

					<td class="product-quantity">
						<?php

							if ( $_product->is_sold_individually() ) {
								$product_quantity = sprintf( '1 <input type="hidden" name="cart[%s][qty]" value="1" />', $cart_item_key );
							} else {
								//if(($mininc=get_custom_field('mininc')=="")) $mininc=1;
								$post_meta=get_post_meta($product_id,'mininc');
								if(($mininc=$post_meta[0])=="") $mininc=1;
								$product_quantity = woocommerce_quantity_input( array(
									'input_name'  => "cart[{$cart_item_key}][qty]",
									'input_value' => $cart_item['quantity'],
									'max_value'   => $_product->backorders_allowed() ? '' : $_product->get_stock_quantity(),
									'min_value' =>$mininc,
								), $_product, false );
							}

							echo apply_filters( 'woocommerce_cart_item_quantity', $product_quantity, $cart_item_key );
						?>
					</td>

					<td class="product-subtotal">
						<?php
							echo apply_filters( 'woocommerce_cart_item_subtotal', WC()->cart->get_product_subtotal( $_product, $cart_item['quantity'] ), $cart_item, $cart_item_key );
						?>
					</td>
				</tr>
				<?php
			}
		}

		do_action( 'woocommerce_cart_contents' );
		?>

https://www.ads-software.com/plugins/custom-content-type-manager/