检查wpcf7_before_send_mail操作和add_extra_attachments函数以添加附件，例如：

add_action('wpcf7_before_send_mail', 'your_custom_function', 10, 3);

function your_custom_function( $contact_form, $abort, $submission ) {

  $file_path = array(
    'path 1',
    'path 2',
    'path 3',
  );

  $template = 'mail'; // use 'mail' if you want to attach to the defautl email.
  $template_2 = 'mail_2'; // use 'mail_2' if you want to attach to Mail (2).

  $submission->add_extra_attachments( $file_path, $template ); // attaches to the default email
  $submission->add_extra_attachments( $file_path, $template_2 ); // attaches to mail (2)

}

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