def linked_list_add(head, name, phone):
    curr = head
    while curr is not None:
        if curr['name'] == name:
            curr['phone'] = phone
            return head
        curr = curr['next']

    new_node = {'name': name, 'phone': phone, 'next': None}
    if head is None:
        return new_node

    curr = head
    while curr['next'] is not None:
        curr = curr['next']
    curr['next'] = new_node
    return head


def linked_list_find(head, name):
    curr = head
    while curr is not None:
        if curr['name'] == name:
            return curr['phone']
        curr = curr['next']
    return None


def linked_list_remove(head, name):
    if head is None:
        return None

    if head['name'] == name:
        return head['next']

    prev = head
    curr = head['next']
    while curr is not None:
        if curr['name'] == name:
            prev['next'] = curr['next']
            return head
        prev = curr
        curr = curr['next']
    return head


def linked_list_collect_all(head):
    records = []
    curr = head
    while curr is not None:
        records.append((curr['name'], curr['phone']))
        curr = curr['next']
    records.sort(key=lambda pair: pair[0])
    return records


# Quick test 
if __name__ == '__main__':
    lst = None
    lst = linked_list_add(lst, 'Alice', '111-222')
    lst = linked_list_add(lst, 'Bob', '333-444')
    lst = linked_list_add(lst, 'Alice', '555-666')
    print(linked_list_find(lst, 'Alice'))  # 555-666
    print(linked_list_collect_all(lst))    # [('Alice','555-666'), ('Bob','333-444')]
    lst = linked_list_remove(lst, 'Bob')
    print(linked_list_collect_all(lst))    # [('Alice','555-666')]