code: def get_output_shapes(self):
          
          outputs = self.execs[0].outputs
          shapes = [out.shape for out in outputs]
  
          concat_shapes = []
          for key, the_shape, axis in zip(self.symbol.list_outputs(), shapes, self.output_layouts):
              the_shape = list(the_shape)
              if axis >= 0:
                  the_shape[axis] = self.batch_size
              concat_shapes.append((key, tuple(the_shape)))
          return concat_shapes
docs: Get the shapes of the outputs.