diff --git a/mbcp/mp_math/equation.py b/mbcp/mp_math/equation.py
index e6e5ce8..95d6483 100644
--- a/mbcp/mp_math/equation.py
+++ b/mbcp/mp_math/equation.py
@@ -57,6 +57,7 @@ def get_partial_derivative_func(func: MultiVarsFunc, var: int | tuple[int, ...],
     Raises:
         ValueError: 无效变量类型
     """
+    # 内部函数不注释，以防止生成文档
     if isinstance(var, int):
         def partial_derivative_func(*args: Var) -> Var:
             args_list_plus = list(args)