def get_model(sbml):
    """
    return the model of a SBML
    """
    model_element = None
    for e in sbml:
        if e.tag[0] == '{':
            uri, tag = e.tag[1:].split('}')
        else:
            tag = e.tag
        if tag == 'model':
            model_element = e
            break
    return model_element
