'Transfer the certificate item from one course to another.
Do not use this generally, since certificate items are directly associated with a particular purchase.
This should only be used when a single course to a new location. This cannot be used when transferring
from one course to many.
Args:
source_key (str): The course key string representation for the original course.
enrollment (CourseEnrollment): The original enrollment to move the certificate item from.
user (User): The user to transfer the item for.
dest_keys (list): A list of course key strings to transfer the item to.
new_enrollment (CourseEnrollment): The new enrollment to associate the certificate item with.
Returns:
None'

@staticmethod
def _transfer_certificate_item(source_key, enrollment, user, dest_keys, new_enrollment):

    try:
        certificate_item = CertificateItem.objects.get(course_id=source_key, course_enrollment=enrollment)
    except CertificateItem.DoesNotExist:
        print u'No    certificate    for    {}'.format(user)
        return
    certificate_item.course_id = dest_keys[0]
    certificate_item.course_enrollment = new_enrollment
