def get_tfp_model_obj(tfp_code):
    """Executes the generated python program, and returns an
    un-instantiated model object
    
    Parameters
    ----------
    tfp_code : string
        the program to execute
    
    Returns
    -------
    tfd.Distribution
        the model class
    """    
    exec_dict = {}
    exec(tfp_code, exec_dict)
    return exec_dict["model"]