如何在keras中限制某个范围内的权重

from tensorflow.keras.layers import Dense
from tensorflow.keras.constraints import max_norm

model.add(Dense(64, kernel_constraint=max_norm(2.)))

from tensorflow.keras import backend as K
from tensorflow.keras.constraints import Constraint

class MinMaxConstraint(Constraint):
    def __init__(self, min_value, max_value):
        self.min_value = min_value
        self.max_value = max_value

    def __call__(self, w):
        return K.clip(w, self.min_value, self.max_value)

    def get_config(self):
        return {'min_value': float(self.min_value), 'max_value': float(self.max_value)}

# 使用自定义约束
model.add(Dense(64, kernel_constraint=MinMaxConstraint(-0.5, 0.5)))