def _sub_func(expr, sub_dict):
    if expr in sub_dict:
        return sub_dict[expr]
    elif not expr.args or expr.is_Derivative:
        return expr
Do kinit ops for the kerberos authentication
dataset/ETHPy150Open sympy/sympy/sympy/physics/mechanics/functions.py/_sub_func--crossover with--dataset/ETHPy150Open idumpling/robotx/robotx/core/nitrateclient.py/TCMS.kinit