code: func InEpsilon(t TestingT, expected interface{}, actual interface{}, epsilon float64, msgAndArgs ...interface{}) {
  	if h, ok := t.(tHelper); ok {
  		h.Helper()
  	}
  	if assert.InEpsilon(t, expected, actual, epsilon, msgAndArgs...) {
  		return
  	}
  	t.FailNow()
  }
docs: // InEpsilon asserts that expected and actual have a relative error less than epsilon