'Element-wise clip all parameter tensors to between
``-abs_bound`` and ``+abs_bound`` in a list of layers.
Arguments:
layer_list (list): List of layers
be (Backend object): Backend in which the tensor resides
abs_bound (float, optional): Value to element-wise clip gradients
or parameters. Defaults to None.'

@staticmethod
def clip_param_in_layers(layer_list, abs_bound=None):

    param_list = get_param_list(layer_list)
    for ((param, grad), states) in param_list:
        if abs_bound:
            param[:] = param.backend.clip(param, (- abs(abs_bound)), abs(abs_bound))
