def can_link_to(person, contact, model):
    """
    Determines whether or not the specified person can form a social network
    link to the specified contact.

    :param person: The person wanting to link.
    :param contact: The contact to determine link eligibility.
    :param model: The model to use.
    """
    if model.require_mutual and \
                    len(contact.contacts) >= contact.max_contacts and \
            not person.unique_id in contact.contacts:
        return False
    return True