199 lines
8.4 KiB
Python
199 lines
8.4 KiB
Python
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import torch
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import torch.nn as nn
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from torch.nn import functional as nnf
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from enum import Enum
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from transformers import GPT2LMHeadModel
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from typing import Tuple, Optional
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def get_clapcap(name: str):
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if name == "ClapCaption":
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return ClapCaptionModel
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else:
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raise Exception('The ClapCap model {} is incorrect or not supported'.format(name))
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class MappingType(Enum):
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MLP = 'mlp'
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Transformer = 'transformer'
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class MLP(nn.Module):
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def __init__(self, sizes: Tuple[int, ...], bias=True, act=nn.Tanh):
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super(MLP, self).__init__()
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layers = []
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for i in range(len(sizes) - 1):
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layers.append(nn.Linear(sizes[i], sizes[i + 1], bias=bias))
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if i < len(sizes) - 2:
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layers.append(act())
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self.model = nn.Sequential(*layers)
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def forward(self, x: torch.Tensor) -> torch.Tensor:
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return self.model(x)
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class MlpTransformer(nn.Module):
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def __init__(self, in_dim, h_dim, out_d: Optional[int] = None, act=nnf.relu, dropout=0.):
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super().__init__()
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out_d = out_d if out_d is not None else in_dim
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self.fc1 = nn.Linear(in_dim, h_dim)
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self.act = act
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self.fc2 = nn.Linear(h_dim, out_d)
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self.dropout = nn.Dropout(dropout)
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def forward(self, x):
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x = self.fc1(x)
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x = self.act(x)
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x = self.dropout(x)
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x = self.fc2(x)
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x = self.dropout(x)
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return x
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class MultiHeadAttention(nn.Module):
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def __init__(self, dim_self, dim_ref, num_heads, bias=True, dropout=0.):
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super().__init__()
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self.num_heads = num_heads
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head_dim = dim_self // num_heads
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self.scale = head_dim ** -0.5
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self.to_queries = nn.Linear(dim_self, dim_self, bias=bias)
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self.to_keys_values = nn.Linear(dim_ref, dim_self * 2, bias=bias)
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self.project = nn.Linear(dim_self, dim_self)
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self.dropout = nn.Dropout(dropout)
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def forward(self, x, y=None, mask=None):
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y = y if y is not None else x
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b, n, c = x.shape
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_, m, d = y.shape
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# b n h dh
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queries = self.to_queries(x).reshape(b, n, self.num_heads, c // self.num_heads)
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# b m 2 h dh
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keys_values = self.to_keys_values(y).reshape(b, m, 2, self.num_heads, c // self.num_heads)
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keys, values = keys_values[:, :, 0], keys_values[:, :, 1]
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attention = torch.einsum('bnhd,bmhd->bnmh', queries, keys) * self.scale
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if mask is not None:
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if mask.dim() == 2:
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mask = mask.unsqueeze(1)
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attention = attention.masked_fill(mask.unsqueeze(3), float("-inf"))
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attention = attention.softmax(dim=2)
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out = torch.einsum('bnmh,bmhd->bnhd', attention, values).reshape(b, n, c)
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out = self.project(out)
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return out, attention
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class TransformerLayer(nn.Module):
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def forward_with_attention(self, x, y=None, mask=None):
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x_, attention = self.attn(self.norm1(x), y, mask)
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x = x + x_
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x = x + self.mlp(self.norm2(x))
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return x, attention
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def forward(self, x, y=None, mask=None):
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x = x + self.attn(self.norm1(x), y, mask)[0]
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x = x + self.mlp(self.norm2(x))
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return x
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def __init__(self, dim_self, dim_ref, num_heads, mlp_ratio=4., bias=False, dropout=0., act=nnf.relu,
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norm_layer: nn.Module = nn.LayerNorm):
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super().__init__()
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self.norm1 = norm_layer(dim_self)
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self.attn = MultiHeadAttention(dim_self, dim_ref, num_heads, bias=bias, dropout=dropout)
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self.norm2 = norm_layer(dim_self)
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self.mlp = MlpTransformer(dim_self, int(dim_self * mlp_ratio), act=act, dropout=dropout)
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class Transformer(nn.Module):
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def __init__(self, dim_self: int, num_heads: int, num_layers: int, dim_ref: Optional[int] = None,
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mlp_ratio: float = 2., act=nnf.relu, norm_layer: nn.Module = nn.LayerNorm, enc_dec: bool = False):
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super(Transformer, self).__init__()
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dim_ref = dim_ref if dim_ref is not None else dim_self
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self.enc_dec = enc_dec
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if enc_dec:
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num_layers = num_layers * 2
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layers = []
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for i in range(num_layers):
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if i % 2 == 0 and enc_dec: # cross
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layers.append(TransformerLayer(dim_self, dim_ref, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
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elif enc_dec: # self
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layers.append(TransformerLayer(dim_self, dim_self, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
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else: # self or cross
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layers.append(TransformerLayer(dim_self, dim_ref, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
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self.layers = nn.ModuleList(layers)
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def forward_with_attention(self, x, y=None, mask=None):
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attentions = []
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for layer in self.layers:
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x, att = layer.forward_with_attention(x, y, mask)
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attentions.append(att)
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return x, attentions
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def forward(self, x, y=None, mask=None):
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for i, layer in enumerate(self.layers):
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if i % 2 == 0 and self.enc_dec: # cross
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x = layer(x, y)
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elif self.enc_dec: # self
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x = layer(x, x, mask)
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else: # self or cross
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x = layer(x, y, mask)
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return x
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class TransformerMapper(nn.Module):
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def __init__(self, dim_clip: int, dim_embedding: int, prefix_length: int, clip_length: int, num_layers: int = 8):
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super(TransformerMapper, self).__init__()
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self.clip_length = clip_length
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self.transformer = Transformer(dim_embedding, 8, num_layers)
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self.linear = nn.Linear(dim_clip, clip_length * dim_embedding)
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self.prefix_const = nn.Parameter(torch.randn(prefix_length, dim_embedding), requires_grad=True)
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def forward(self, x):
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x = self.linear(x).view(x.shape[0], self.clip_length, -1)
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prefix = self.prefix_const.unsqueeze(0).expand(x.shape[0], *self.prefix_const.shape)
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prefix = torch.cat((x, prefix), dim=1)
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out = self.transformer(prefix)[:, self.clip_length:]
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return out
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class ClapCaptionModel(nn.Module):
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def __init__(self, clap, text_decoder: str, prefix_length: int, clip_length: Optional[int] = None, prefix_size: int = 512,
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num_layers: int = 8, normalize_prefix: bool = True, mapping_type: str = None,\
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freeze_audio_encoder_weights: bool = True, freeze_gpt_weights: bool = True):
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super(ClapCaptionModel, self).__init__()
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self.clap = clap.audio_encoder
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self.prefix_length = prefix_length
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self.normalize_prefix = normalize_prefix
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self.gpt = GPT2LMHeadModel.from_pretrained(text_decoder)
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self.gpt_embedding_size = self.gpt.transformer.wte.weight.shape[1]
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if mapping_type == 'mlp':
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self.clap_project = MLP((prefix_size, (self.gpt_embedding_size * prefix_length) // 2,
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self.gpt_embedding_size * prefix_length))
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else:
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self.clap_project = TransformerMapper(prefix_size, self.gpt_embedding_size, prefix_length,
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clip_length, num_layers)
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# Freeze all CLAP parameters
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if freeze_audio_encoder_weights:
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for p in self.clap.parameters():
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p.requires_grad = False
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if freeze_gpt_weights:
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for p in self.gpt.parameters():
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p.requires_grad = False
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def get_dummy_token(self, batch_size: int, device: torch.device) -> torch.Tensor:
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return torch.zeros(batch_size, self.prefix_length, dtype=torch.int64, device=device)
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def forward(self, audios: torch.Tensor, tokens: torch.Tensor, mask: Optional[torch.Tensor] = None,
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labels: Optional[torch.Tensor] = None):
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# get audio embeddings
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prefix, _ = self.clap(audios)
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# normalize prefix (audio embedding)
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if self.normalize_prefix:
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prefix = prefix / prefix.norm(2, -1).reshape(-1,1)
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embedding_text = self.gpt.transformer.wte(tokens['input_ids'])
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prefix_projections = self.clap_project(prefix).view(-1, self.prefix_length, self.gpt_embedding_size)
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embedding_cat = torch.cat((prefix_projections, embedding_text), dim=1)
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if labels is not None:
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dummy_token = self.get_dummy_token(tokens['input_ids'].shape[0], tokens['input_ids'].device)
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labels = torch.cat((dummy_token, tokens), dim=1)
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out = self.gpt(inputs_embeds=embedding_cat, labels=labels, attention_mask=mask)
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return out |