class_docstr: A NumPy ndarray-like object abstracted as shape and dtype.
  
  Main use is for representing input and output signatures.
code: def __repr__(self):
      return "ShapeDtype{{shape:{}, dtype:{}}}".format(
          self.shape, self.dtype
      )
  
file_path: trax/trax/shapes.py
imports: import numpy
  import tensorflow
label_desc: Use image node_id 4 for calling the ShapeDtype obj's underlying member method code with example usage: obj.__repr__() and returns: str