Fix concatenate incorrect shape error

app.py

@@ -39,8 +39,9 @@ def train(data: str, message: str):
         flatten_layer = Flatten()(conv3_layer)
         attn_flatten_layer = Flatten()(attn_layer)
         conv1_flatten_layer = Flatten()(conv1_layer)
+        conv2_flatten_layer = Flatten()(conv2_layer)
         conv3_flatten_layer = Flatten()(conv3_layer)
-        concat1_layer = Concatenate()([flatten_layer, attn_flatten_layer, conv1_flatten_layer, conv2_layer, conv3_flatten_layer])
+        concat1_layer = Concatenate()([flatten_layer, attn_flatten_layer, conv1_flatten_layer, conv2_flatten_layer, conv3_flatten_layer])
         dense1_layer = Dense(512, activation="linear")(concat1_layer)
         prelu1_layer = PReLU()(dense1_layer)
         dropout_layer = Dropout(0.3)(prelu1_layer)