UnorderedList class

An unordered list consists of an initial "head" of the list which may point to a Node, which in turn may point to other Node objects which collectively make up the entire list.

Write an UnorderedList class that begins with this constructor:

import Node

class UnorderedList(object):
"""Maintains an unordered list via a linked series of Nodes
"""

def __init__(self):
    self.head = None

Then continue developing the the class by writing the following methods:

• add(item) allows us to add an item to the beginning of the list. (For the moment, we're going to assume it's a unique item, and that it's not already present on the list.)
• remove(item) removes the specified item from the list. This assumes that the item is already in the list.
• search(item) looks for the specified item in the list, and returns True it if is there somewhere.
• is_empty() returns True if the list is empty.
• length() returns the number of items in the list.
• append(item) adds the item to the end of the list.
• index(item) returns the position of the item in the list (and assumes it is in the list)
• insert(pos, item) adds a new item to the list at the specified position. This assumes that the item is not already on the list and that the position exists.
• pop() removes the last item from the list and returns it.
• pop(pos) removes the item at the specified position and returns it.

In addition to these methods, it will certainly be helpful to you to have a __repr__ method that you can use to print out the state of your unordered list.

def __repr__(self):
    """Creates a representation of the list suitable for printing,
    debugging.
    """
    result = "UnorderedList["
    next_node = self.head
    while next_node != None:
        result += str(next_node.get_data()) + ","
        next_node = next_node.get_next()
    result = result + "]"
    return result