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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 _reporthook(t):
 """ ``reporthook`` to use with ``urllib.request`` that prints the process of the download. Uses ``tqdm`` for progress bar. **Reference:** https://github.com/tqdm/tqdm Args: t (tqdm.tqdm) Progress bar. Example: """

    last_b = [0]

    def inner(b=1, bsize=1, tsize=None):
        """
        Args:
            b (int, optional): Number of blocks just transferred [default: 1].
            bsize (int, optional): Size of each block (in tqdm units) [default: 1].
            tsize (int, optional): Total size (in tqdm units). If [default: None] remains unchanged.
        """
        if tsize is not None:
            t.total = tsize
        t.update((b - last_b[0]) * bsize)
        last_b[0] = b

    return inner