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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 download_all(data_home=None, replace=False):
 """ Downloads all the example datasets to the data directory specified by ``get_data_home``. This function ensures that all datasets are available for use with the examples. """

    for _, meta in DATASETS.items():
        download_data(
            meta['url'], meta['signature'], data_home=data_home, replace=replace
        )

    print(
        "Downloaded {} datasets to {}".format(len(DATASETS), get_data_home(data_home))
    )