Do not show billing fields

We have worked with developer who is away now.
He has added code to functions.php to remove some woocommerce billing fields, like Company, State and others.

This code:

function remove_billing_fields( $fields = array() ) {
	unset($fields['billing_address_2']);
	unset($fields['billing_state']);
	unset($fields['billing_city']);
	unset($fields['billing_postcode']);
	unset($fields['billing_country']);
	return $fields;
}
add_filter('woocommerce_billing_fields', 'remove_billing_fields');

To show fields to customers I have removed some of them from code.
But there no fields showing. Also after cache has cleared.

Please. What I have to fix?

Thanks for any help!

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