docstr: Parameters
  ----------
  mem_length
      The memory length of the model
docstr_tok: ["Parameters","--","--","--","--","--","mem_length","The","memory","length","of","the","model"]
code: def set_mem_length(self, mem_length: int):
      """
  
      Parameters
      ----------
      mem_length
          The memory length of the model
      """
      self._cfg.defrost()
      self._cfg.MODEL.mem_length = mem_length
      self._cfg.freeze()
  
imports: import numpy
  import mxnet
  from mxnet import use_np, np, npx
  from mxnet.gluon import nn, Block, HybridBlock, Parameter
  from ..attention_cell import multi_head_dot_attn, gen_self_attn_mask, gen_mem_attn_mask, RelAttentionScoreCell, MultiHeadAttentionCell
  from ..layers import get_activation, PositionalEmbedding, PositionwiseFFN, AdaptiveEmbedding, ProjectedAdaptiveLogSoftmaxWithLoss
  from ..utils.config import CfgNode
  from ..sequence_sampler import BaseStepDecoder
label_desc: Use image node_id 8 for calling the TransformerXLForLM obj's underlying member method code with example usage: obj.set_mem_length(mem_length) without return types