Bug: MAC Address Accepts Invalid 7-Byte Length

[darthsiderius]

Problem

MacAddress class accepts "11:22:33:44:55:66:77" as valid when it should reject 7-byte MAC addresses.

Expected

Should raise validation error - only 6, 8, or 20 byte MAC addresses are valid.

Actual

Accepts and processes the invalid 7-byte address.

Root Cause

This validation should fail but doesn't:

if len(parts) * partbytes // 2 not in (6, 8, 20): # 7 * 2 // 2 = 7, not in (6,8,20)