class Queue:
    """
    Provides a rudimentary implementation of the queue data structure

    Attributes
    ----------
    queue : (list of any) the underlying queue of objects

    Methods
    -------
    is_empty(): (bool) returns whether the queue is empty
    add(item): (None) adds the item at the back of the queue
    remove(): (any) removes and returns the item from the front of the queue

    """

    def __init__(self, initial_contents=[]):
        self.queue = initial_contents[:]

    def is_empty(self):
        """
        returns whether the queue is empty
        :return: (bool) whether the queue is empty
        """
        return self.queue == []

    def add(self, item):
        """
        adds the item at the back of the queue
        :param item: (any) the item to add at the back of the queue
        :return: (None)
        """
        self.queue.append(item)

    def remove(self):
        """
        removes and returns the item from the front of the queue
        :return: (any) the item from the front of the queue
        """
        return self.queue.pop(0)

    def __str__(self):
        return "The queue contains: " + str(self.queue)


def main():
    q = Queue()
    print(q)

    q = Queue([1, 2, 3, 4])
    print(q)

    q = Queue()
    q.add(1)
    q.add(10)
    q.add(2)
    print(q)

    q.remove()
    print(q)
    q.remove()
    print(q)
    q.remove()
    print(q)

if __name__ == "__main__":
    main()