class_docstr: Raise error for unknown layer arguments.
  
  Args:
    arg_name: TF Encrypted Keras layer argument name (string)
    layer_sign: TensorFlow Keras layer signature (dict)
    tf_layer_name: TensorFlow Keras layer name (string)
class_docstr_tok: ["Raise","error","for","unknown","layer","arguments",".","Args",":","arg_name",":","TF","Encrypted","Keras","layer","argument","name","(","string",")","layer_sign",":","TensorFlow","Keras","layer","signature","(","dict",")","tf_layer_name",":","TensorFlow","Keras","layer","name","(","string",")"]
code: def __str__(self):
      msg = (
          "Argument '{arg_name}' is not part of the "
          "signature for '{layer_name}' layers: {layer_sign}"
      )
      return msg.format(
          arg_name=self.arg_name,
          layer_name=self.layer_name,
          layer_sign=self.layer_sign.keys(),
      )
  
file_path: tf-encrypted/tf_encrypted/keras/layers/layers_utils.py
imports: import inspect
  import tensorflow
label_desc: Use image node_id 2 for calling the UnknownLayerArgError obj's underlying member method code with example usage: obj.__str__() and returns: msg