How do I parse this data attribute array with a template?

Email sensor contains data attribute:

data:
  - subject: You're now paying a higher rate - ways to save
    received: 2024-01-04T23:36:05+0000
    to:
      - daniel@xxxxxx
    cc: []
    sender: [email protected]
    has_attachments: false
    importance: normal
    is_read: false
    body: >-
      You've reached Step 2 ratesRead this email onlineDear Daniel,Account
      number: XXXXXXXXXX92You've reached Step 2 pricing on January 04, 2024,

I want a true|false template based on a string in the subject:

{{ 'now paying a higher rate' in state_attr('sensor.bc_hydro_step_2','data') }}
{{ 'your bill is ready' in state_attr('sensor.bc_hydro_step_2','data') }}
{{ state_attr('sensor.bc_hydro_step_2','data') }}

{{ 'now paying a higher rate' in
   state_attr('sensor.bc_hydro_step_2','data')['subject'] }}

(wrapped only for readability, can be on one line)

Thanks! That looks like it’ll work.
I magaed to come up with the following based on an example from RogerSelwyn (Office 365 Integration).
He suggested I start with this:

  - sensor:
      - name: environment_heatloss
        unique_id: environment_heatloss
        unit_of_measurement: "%"
        state: >-
          {% for insight in state_attr('binary_sensor.homelink_environment', 'insights') if insight.type == "HEATLOSS" -%}
            {{ insight.value }} 
          {% endfor %}

and I arrived at this which works:

{% for array in state_attr('sensor.bc_hydro_e_mail', 'data') if array.subject == "You're now paying a higher rate - ways to save"-%}
True
{% else %}
False 
{% endfor %}

but I like yours better!

My automatic rate change based on emails from BCHydro is working!

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