code: func InDeltaf(t TestingT, expected interface{}, actual interface{}, delta float64, msg string, args ...interface{}) bool {
  	if h, ok := t.(tHelper); ok {
  		h.Helper()
  	}
  	return InDelta(t, expected, actual, delta, append([]interface{}{msg}, args...)...)
  }
docs: // InDeltaf asserts that the two numerals are within delta of each other.
  //
  // 	 assert.InDeltaf(t, math.Pi, (22 / 7.0, "error message %s", "formatted"), 0.01)