code: function closeTo($value, float $delta): self {
      return $this->expect($this->target, equalTo($value, $delta));
    }
docs: Reports an error if the target is not equal to the specified value, within a given delta range.
  @param int|float $value The value to compare.
  @param float $delta The allowed distance between two values to consider them equal.
  @return self This instance.