def create_contact_person(client, organization_id, contact_id, name, country_code, email=None):
    """
    Creates a contact person object in Billy:
    https://www.billy.dk/api/#v2contactpersons
    """
    contact = {
        'name': name,
        'email': email,
        'isPrimary': True,
        'contactId': contact_id,
    }
    response = client.request('POST', '/contactPersons', {'contactPerson': contact})

    return response['contactPersons'][0]['id']