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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add(self, item):
 """ Add an item to the work queue. :param item: The work item to add. An item may be of any type; however, if it is not hashable, then the work queue must either be initialized with ``unique`` set to ``False``, or a ``key`` callable must have been provided. """


        # Are we to uniquify work items?
        if self._unique:
            key = self._key(item) if self._key else item

            # If it already has been added to the queue, do nothing
            if key in self._seen:
                return

            self._seen.add(key)

        # Add the item to the queue
        self._work.append(item)

        # We'll keep a count of the number of items that have been
        # through the queue
        self._count += 1