<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def l2_regularizer(weight=1.0, scope=None):
 """Define a L2 regularizer. Args: weight: scale the loss by this factor. scope: Optional scope for name_scope. Returns: a regularizer function. """

  def regularizer(tensor):
    with tf.name_scope(scope, 'L2Regularizer', [tensor]):
      l2_weight = tf.convert_to_tensor(weight,
                                       dtype=tensor.dtype.base_dtype,
                                       name='weight')
      return tf.multiply(l2_weight, tf.nn.l2_loss(tensor), name='value')
  return regularizer