def __SXname__(x):
    """
    Returns the name of casadi.SX symbolics

    Parameters
    ----------
    x : list[casadi.SX] or casadi.SX
        List of casadi symbolics or just casadi symbolics.

    Returns
    -------
    list[str] or str
        List of name of symbolics or just name of symbolics
    """
    if isinstance(x, list):
        nameList = []
        for tmp in x:
            z = str(tmp)
            z = z.split('_')
            nameList.append(z[0])

        return nameList
    else:
        z = str(x[0])
        z = z.split('_')
        return z[0]