def raw_skin_tone_variants
      return [] if custom? || !skin_tones?
      raw_normalized = raw.sub(VARIATION_SELECTOR_16, "")
      idx = raw_normalized.index(ZERO_WIDTH_JOINER)
      SKIN_TONES.map do |modifier|
        if raw_normalized == PEOPLE_HOLDING_HANDS
          # special case to apply the modifier to both persons
          raw_normalized[0...idx] + modifier + raw_normalized[idx..nil] + modifier
        elsif idx
          # insert modifier before zero-width joiner
          raw_normalized[0...idx] + modifier + raw_normalized[idx..nil]
        else
          raw_normalized + modifier
        end
      end
    end
Raw Unicode strings for each skin tone variant of this emoji. The result is an empty array
unless the emoji supports skin tones.

Note: for emojis that depict multiple people (e.g. couples or families), this will not produce
every possible permutation of skin tone per person.