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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 _read_ssh_key():
    '''
    Inner function for read_ssh_key, suitable for passing to our
    Executor.

    '''
    default_data_dir = Path(Path.home(), ".local", "share", "juju")
    juju_data = os.environ.get("JUJU_DATA", default_data_dir)
    ssh_key_path = Path(juju_data, 'ssh', 'juju_id_rsa.pub')
    with ssh_key_path.open('r') as ssh_key_file:
        ssh_key = ssh_key_file.readlines()[0].strip()
    return ssh_key