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))
    )