Preventing WordPress from Sending emails

no_emails.php

function childtheme_no_emails( &$phpmailer ) {
	// Empty out the values that may be set
	$phpmailer->ClearAllRecipients();
	$phpmailer->ClearAttachments();
	$phpmailer->ClearCustomHeaders();
	$phpmailer->ClearReplyTos();
}
add_action( 'phpmailer_init', 'childtheme_no_emails', 99, 1 );