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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 get_data_home(data_home=None):
 """Return the path of the arviz data dir. This folder is used by some dataset loaders to avoid downloading the data several times. By default the data dir is set to a folder named 'arviz_data' in the user home folder. Alternatively, it can be set by the 'ARVIZ_DATA' environment variable or programmatically by giving an explicit folder path. The '~' symbol is expanded to the user home folder. If the folder does not already exist, it is automatically created. Parameters data_home : str | None The path to arviz data dir. """

    if data_home is None:
        data_home = os.environ.get("ARVIZ_DATA", os.path.join("~", "arviz_data"))
    data_home = os.path.expanduser(data_home)
    if not os.path.exists(data_home):
        os.makedirs(data_home)
    return data_home