code: def send_activation_email(user, site):
      
      ctx_dict = {'activation_key': user.api_registration_profile.activation_key,
                  'expiration_days': get_settings('REGISTRATION_API_ACCOUNT_ACTIVATION_DAYS'),
                  'site': site}
      subject = render_to_string('registration_api/activation_email_subject.txt',
                                 ctx_dict)
      # Email subject *must not* contain newlines
      subject = ''.join(subject.splitlines())
      message = render_to_string('registration_api/activation_email.txt',
                                 ctx_dict)
      user.email_user(subject, message, settings.DEFAULT_FROM_EMAIL)
docs: Send an activation email to the ``user``.
      The activation email will make use of two templates:
  
      ``registration/activation_email_subject.txt``
      This template will be used for the subject line of the
      email. Because it is used as the subject line of an email,
      this template's output **must** be only a single line of
      text; output longer than one line will be forcibly joined
      into only a single line.
  
      ``registration/activation_email.txt``
      This template will be used for the body of the email.
  
      These templates will each receive the following context
      variables:
  
      ``activation_key``
      The activation key for the new account.
  
      ``expiration_days``
      The number of days remaining during which the account may
      be activated.
  
      ``site``
      An object representing the site on which the user
      registered; depending on whether ``django.contrib.sites``
      is installed, this may be an instance of either
      ``django.contrib.sites.models.Site`` (if the sites
      application is installed) or
      ``django.contrib.sites.models.RequestSite`` (if
      not). Consult the documentation for the Django sites
      framework for details regarding these objects' interfaces.