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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def send_mass_user_template_mail(subject_template, body_template, users, context):
 """ Similar to `send_mass_template_mail` this function renders the given templates into email subjects and bodies. The emails are send one-by-one. """

    message_tuples = []
    for user in users:
        context['user'] = user
        subject, body = render_mail_template(subject_template, body_template, context)

        message_tuples.append((subject, body, conf.get('DEFAULT_FROM_EMAIL'), [user.email]))

    if message_tuples:
        send_mass_mail(message_tuples)