_1 refers to that corresponding to the second text encoder. Otherwise, it is from the first.  forward  < source > ( hidden_states: Optional = None hidden_states_1: Optional = None attention_mask: Optional = None attention_mask_1: Optional = None  )     AudioLDM2UNet2DConditionModel  class diffusers.AudioLDM2UNet2DConditionModel  < source > ( sample_size: Optional = None in_channels: int = 4 out_channels: int = 4 flip_sin_to_cos: bool = True freq_shift: int = 0 down_block_types: Tuple = ('CrossAttnDownBlock2D', 'CrossAttnDownBlock2D', 'CrossAttnDownBlock2D', 'DownBlock2D') mid_block_type: Optional = 'UNetMidBlock2DCrossAttn' up_block_types: Tuple = ('UpBlock2D', 'CrossAttnUpBlock2D', 'CrossAttnUpBlock2D', 'CrossAttnUpBlock2D') only_cross_attention: Union = False block_out_channels: Tuple = (320, 640, 1280, 1280) layers_per_block: Union = 2 downsample_padding: int = 1 mid_block_scale_factor: float = 1 act_fn: str = 'silu' norm_num_groups: Optional = 32 norm_eps: float = 1e-05 cross_attention_dim: Union = 1280 transformer_layers_per_block: Union = 1 attention_head_dim: Union = 8 num_attention_heads: Union = None use_linear_projection: bool = False class_embed_type: Optional = None num_class_embeds: Optional = None upcast_attention: bool = False resnet_time_scale_shift: str = 'default' time_embedding_type: str = 'positional' time_embedding_dim: Optional = None time_embedding_act_fn: Optional = None timestep_post_act: Optional = None time_cond_proj_dim: Optional = None conv_in_kernel: int = 3 conv_out_kernel: int = 3 projection_class_embeddings_input_dim: Optional = None class_embeddings_concat: bool = False  )   Parameters   sample_size (int or Tuple[int, int], optional, defaults to None) —