def get_is_post_signup(request):
    """If the session contains a true value for ``is_post_signup``, then wipe
      it and return ``True``.  Otherwise, return ``False``.

      Setup::

          >>> from mock import Mock
          >>> mock_request = Mock()

      If the session contains a true value for ``is_post_signup``, then wipe
      it and return ``True``::

          >>> mock_request.session = {'is_post_signup': True}
          >>> get_is_post_signup(mock_request)
          True
          >>> mock_request.session
          {}

      Otherwise, return ``False``::

          >>> get_is_post_signup(mock_request)
          False

    """
    is_post_signup = request.session.get('is_post_signup', False)
    if is_post_signup:
        del request.session['is_post_signup']
        return True
    return False
