code: func (c *Call) On(methodName string, arguments ...interface{}) *Call {
  	return c.Parent.On(methodName, arguments...)
  }
docs: // On chains a new expectation description onto the mocked interface. This
  // allows syntax like.
  //
  //    Mock.
  //       On("MyMethod", 1).Return(nil).
  //       On("MyOtherMethod", 'a', 'b', 'c').Return(errors.New("Some Error"))
  //go:noinline