# total_loss

def total_loss():
  loss = K.variable(0.)

  # contribution of content loss
  feature_layers_content = outputs_dict['block5_conv2']
  loss += content_weight * content_loss(feature_layers_content)

  # contribution of style loss
  feature_layers_style = ['block1_conv1', 'block2_conv1',
                         'block3_conv1', 'block4_conv1',
                         'block5_conv1']
  loss += total_style_loss(feature_layers_style) * style_weight

  # contribution of variation loss

  loss += total_variation_weight * total_variation_loss(combination_image)
  return loss