class_docstr: bach: [
      [(4*3xH*W), (4,)]
      [(4*3xH*W), (4,)]
      ...
  ]
code: def __call__(self, batch):
      output = [np.concatenate(d, axis=0) for d in zip(*batch)]
      return output
  
file_path: PaddleOCR/ppocr/data/collate_fn.py
imports: import paddle
  import numbers
  import numpy
  from collections import defaultdict
label_desc: Use image node_id 1 for calling the SSLRotateCollate obj's underlying member method code with example usage: obj.__call__(batch) and returns: output