code: def unknown_shape(ndims=None):
      """Returns an unknown TensorShape, optionally with a known rank.
  
      Args:
        ndims: (Optional) If specified, the number of dimensions in the shape.
  
      Returns:
        An unknown TensorShape.
      """
      if ndims is None:
          return TensorShape(None)
      else:
          return TensorShape([Dimension(None)] * ndims)
  
imports: from .None import compat, dtypes
  from tensorboard.compat.proto import tensor_shape_pb2
label_desc: Use image node_id 3 for calling a global function with example usage: unknown_shape(ndims) and returns: TensorShape, TensorShape