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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_current_revision( database_url: str, version_table: str = DEFAULT_ALEMBIC_VERSION_TABLE) -> str: """ Ask the database what its current revision is. Arguments: database_url: SQLAlchemy URL for the database version_table: table name for Alembic versions """

    engine = create_engine(database_url)
    conn = engine.connect()
    opts = {'version_table': version_table}
    mig_context = MigrationContext.configure(conn, opts=opts)
    return mig_context.get_current_revision()