class_docstr: Affine transform a * x + b
  
  Parameters
  ----------
  a: float
  b: float
class_docstr_tok: ["Affine","transform","a","*","x","+","b","Parameters","--","--","--","--","--","a",":","float","b",":","float"]
code: def backward(self, y: np.ndarray) -> np.ndarray:
      return (y - self.b) / self.a
  
imports: import uuid
  import itertools
  import numpy
  from scipy import stats
  import nevergrad.common.typing
  from .None import utils
label_desc: Use image node_id 3 for calling the Affine obj's underlying member method code with example usage: obj.backward(y) and returns: unknown