code: def stack(
      data,
      ctx: Optional[mx.context.Context] = None,
      dtype: Optional[Type] = np.float32,
      variable_length: bool = False,
      is_right_pad: bool = True,
  ):
      if variable_length and not _is_stackable(data):
          data = _pad_arrays(data, axis=0, is_right_pad=is_right_pad)
      if isinstance(data[0], mx.nd.NDArray):
          # TODO: think about using shared context NDArrays
          #  https://github.com/awslabs/gluonts/blob/42bee73409f801e7bca73245ca21cd877891437c/src/gluonts/dataset/parallelized_loader.py#L157
          return mx.nd.stack(*data)
      if isinstance(data[0], np.ndarray):
          data = mx.nd.array(data, dtype=dtype, ctx=ctx)
      elif isinstance(data[0], (list, tuple)):
          return list(
              stack(
                  t,
                  ctx=ctx,
                  dtype=dtype,
                  variable_length=variable_length,
                  is_right_pad=is_right_pad,
              )
              for t in zip(*data)
          )
      return data
  
file_path: gluonts/src/gluonts/mx/batchify.py
imports: import functools
  from typing import List, Optional, Type
  import mxnet
  import numpy
  from gluonts.dataset.common import DataBatch
label_desc: Use image node_id 4 for calling a global function with example usage: stack(data, ctx, dtype, variable_length, is_right_pad) and returns: data, mx, list