code: def _run(self, X):  # type: ignore
      if len(X.shape) == 0:
          return (sigmoid(X).astype(X.dtype),)
      if X.size == 0:
          return (X,)
      return (self.vf(X).astype(X.dtype),)
  
imports: import numpy
  from onnx.reference.ops._op import OpRunUnaryNum
label_desc: Use image node_id 2 for calling the Sigmoid obj's underlying member method code with example usage: obj._run(X) and returns: self, sigmoid, X