<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def unique(g):
 """ Yield values yielded by ``g``, removing any duplicates. Example ------- [1, 3, 2] """

    yielded = set()
    for value in g:
        if value not in yielded:
            yield value
            yielded.add(value)