 	{id: 'AXXXXXXXX9', cardType: 'twid', expect: false}
 	{id: '0123456789', cardType: 'twid', expect: false}
 
-	# fail test: gender
-	{id: 'D012345678', cardType: 'twid', expect: false} # only 1 or 2 in 2nd character
-	{id: 'C987654321', cardType: 'twid', expect: false} # only 1 or 2 in 2nd character
-	{id: 'E345678901', cardType: 'twid', expect: false} # only 1 or 2 in 2nd character
+	# fail test: gender (2nd character has to be 1 or 2)
+	{id: 'D012345678', cardType: 'twid', expect: false}
+	{id: 'C987654321', cardType: 'twid', expect: false}
+	{id: 'E345678901', cardType: 'twid', expect: false}
 
 	# fail test: checksum
-	{id: 'A234567890', cardType: 'twid', expect: false}
+	{id: 'A234567890', cardType: 'twid', expect: false} # src: Apple Daily TW
 
 
 	# Taiwan Resident Certificate

	{id: 'A5555550', cardType: 'hkid', expect: true}
	{id: 'C5678909', cardType: 'hkid', expect: true} # modify from Caring and Sharing Scheme sample (2019)
	{id: 'AB9876543', cardType: 'hkid', expect: true}
	{id: 'WX1234569', cardType: 'hkid', expect: true}

	# fail test: length
	{id: 'A123456', cardType: 'hkid', expect: false}

	{id: 'A12345670', cardType: 'hkid', expect: false}

	# fail test: checksum
	{id: 'C668668E', cardType: 'hkid', expect: false} # src: SCMP
	{id: 'C5678901', cardType: 'hkid', expect: false} # copy from Caring and Sharing Scheme sample (2019)
	{id: 'Z6833655', cardType: 'hkid', expect: false} # src: Wikipedia
	{id: 'Z6833672', cardType: 'hkid', expect: false} # src: immd.gov.hk

	# false test: other impossible ID, e.g. according to practice
	{id: 'O1234561', cardType: 'hkid', expect: false} # no ID starting with "O"
