How to intercept from the new order template that a payment was made by bank transfer

[andpow]

As the title suggests, I'm trying to intercept the payment gateway from the email template when a user chooses the payment by bank transfer to personalize the message ... my check is as follows but it didn't work:

{% for transaction in order.transactions %}
  {% if transaction.gateway == 'bank_transfer' or transaction.gateway == 'bonifico_bancario' or transaction.gateway == 'Bonifico bancario' or transaction.gateway == 'manual_payments' %}
    {% assign manual_transfer= true %}
  {% endif %}
{% endfor %}

Can anyone help me ?

Thank's