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.

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