def _aval_to_tf_shape(aval: core.AbstractValue) -> Tuple[(Optional[int], ...)]:
    'Generate a TF shape, possibly containing None for polymorphic dimensions.'
    return tuple(map((lambda d: (None if isinstance(d, shape_poly.DimVar) else d)), aval.shape))
Generate a TF shape, possibly containing None for polymorphic dimensions.
def _aval_to_tf_shape(aval: core.AbstractValue) -> Tuple[(Optional[int], ...)]:
    
    return tuple(map((lambda d: (None if isinstance(d, shape_poly.DimVar) else d)), aval.shape))