def _rhs(model_expression):
    """
    Get only the right-hand side of a patsy model expression.

    Parameters
    ----------
    model_expression : str

    Returns
    -------
    rhs : str

    """
    if '~' not in model_expression:
        return model_expression
    else:
        return model_expression.split('~')[1].strip()
dataset/ETHPy150Open UDST/urbansim/urbansim/models/regression.py/_rhs/original