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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 reader(stream, fieldnames=None):
 """Read Items from a stream containing TSV."""

    if not fieldnames:
        fieldnames = load_line(stream.readline())
    for line in stream:
        values = load_line(line)
        item = Item()
        item.__dict__ = dict(zip(fieldnames, values))
        yield item