fix type

Signed-off-by: Ngoc Minh Tran <[email protected]>

Author: minhitbk

art/attacks/evasion/imperceptible_asr/imperceptible_asr_pytorch.py

@@ -90,8 +90,8 @@ def __init__(
         max_iter_2: int = 4000,
         learning_rate_1: float = 0.001,
         learning_rate_2: float = 5e-4,
-        optimizer_1: torch.optim.Optimizer = torch.optim.Adam,
-        optimizer_2: torch.optim.Optimizer = torch.optim.Adam,
+        optimizer_1: "torch.optim.Optimizer" = "torch.optim.Adam",
+        optimizer_2: "torch.optim.Optimizer" = "torch.optim.Adam",
         global_max_length: int = 200000,
         initial_rescale: float = 1.0,
         decrease_factor_eps: float = 0.8,