# Codeblock 19b
   def forward(self, features, captions, attn_mask):  #(1)
       print(f"features\t\t: {features.shape}")
       print(f"captions\t\t: {captions.shape}")
      
       captions = self.embedding(captions)  #(2)
       print(f"after embedding\t\t: {captions.shape}")
      
       captions = captions + self.sinusoidal_embedding()  #(3)
       print(f"after sin embed\t\t: {captions.shape}")
      
       for i, decoder_block in enumerate(self.decoder_blocks):
           captions = decoder_block(features, captions, attn_mask)  #(4)
           print(f"after decoder block #{i}\t: {captions.shape}")
      
       captions = self.linear(captions)  #(5)
       print(f"after linear\t\t: {captions.shape}")
      
       return captions