}
			if h.Typeflag == TypeGNUSparse {
				whyOnlyGNU = "only GNU supports TypeGNUSparse"
				format.mayOnlyBe(FormatGNU)
			} else {
				whyNoGNU = "GNU supports sparse files only with TypeGNUSparse"
				format.mustNotBe(FormatGNU)
			}
			whyNoUSTAR = "USTAR does not support sparse files"
			format.mustNotBe(FormatUSTAR)
		}
	*/

	// Check desired format.