Use of get_params()

Getting an error related to the use of the function get_params() in the snippet for the shortcode below. Appreciate any insights into resolving, thank you.

‘<?php
$calendly_parameters = $request->get_params();
$appointment_details = ‘<p><span class=”text-mixed text-bold text-125″>’ . calendly_parameters[‘invitee_first_name’] . ‘</span>, Here are the details of your meeting with us:</p>’;
$appointment_details = $appointment_details . ‘

‘;
$appointment_details = $appointment_details . ‘
• <span class=”text-bold text-125″>Meeting Start:</span> ‘ . calendly_parameters[‘event_start_time’] . ‘

‘;
$appointment_details = $appointment_details . ‘

• <span class=”text-bold text-125″>Meeting End:</span> ‘ . calendly_parameters[‘event_end_time’] . ‘

‘;
$appointment_details = $appointment_details . ‘

• <span class=”text-bold text-125″>Reminder Email:</span> ‘ . calendly_parameters[‘invitee_email’] . ‘

‘;
$appointment_details = $appointment_details . ‘

• <span class=”text-bold text-125″>Details You Provided to Us:</span><br>’ . calendly_parameters[‘answer_1’] . ‘

‘;
$appointment_details = $appointment_details . ‘

‘;
echo $appointment_details;
?>`

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