code: def forward(
      self, x, attn_mask=None
  ):  # x is in shape[max_len,batch_size,emb_dim]
      atten = multi_head_attention_forward(
          x,
          self.num_heads,
          self.q_proj,
          self.k_proj,
          self.v_proj,
          self.c_proj,
          attn_mask=attn_mask,
      )
  
      return atten
  
imports: from typing import Optional
  import paddle
  import paddle.nn
  from paddle import Tensor
  from paddle.nn import functional
  from paddle.nn import Linear
label_desc: Use image node_id 2 for calling the MultiHeadAttention obj's underlying member method code with example usage: obj.forward(x, attn_mask) and returns: atten