anchor.diff:            "BlockName", 0x300A00FE, "Block Name", VR.kLO, VM.k1, false);
     static const Tag kBlockThickness
         //(300A,0100)
  -      = const Tag.public("BlockThickness", 0x300A0100, "Block Thickness", VR.kDS,
  -          VM.k1, false);
  +      = const Tag.public("BlockThickness", 0x300A0100, "Block Thickness",
  +          VR.kDS, VM.k1, false);
     static const Tag kBlockTransmission
         //(300A,0102)
         = const Tag.public("BlockTransmission", 0x300A0102, "Block Transmission",
  
positive.code:           "Relative Image Position Code Sequence", VR.kSQ, VM.k1, false);
    static const Tag kCameraAngleOfView
        //(0022,001E)
        = const Tag.public("CameraAngleOfView", 0x0022001E, "Camera Angle of View",
            VR.kFL, VM.k1, false);
    static const Tag kStereoPairsSequence
        //(0022,0020)
        = const Tag.public("StereoPairsSequence", 0x00220020,
  
negative.code:     throw new RangeError(msg);
    }
  
    static Tag lookup(int code, [VR vr = VR.kUN]) {
      if (code.isEven) {
        return lookupPublicCode(code, vr);
      } else if (Tag.isPublicCode(code)) {} else if (Tag.isPrivateCode(code)) {
        // *** This should not happen!
        if (Tag.isPrivateCreatorCode(code))
          return new PrivateCreatorTag.unknown("Unknown Creator", code, vr);
      }
      // This should never happen
      throw 'Error: Unknown Tag Code${Tag.toDcm}';
    }
  
    /// Returns a Public Tag, either known or unknown
    static Tag lookupPublicCode(int code,
        [VR vr = VR.kUnknown, bool shouldThrow = true]) {
      assert(code.isEven, 'Call to lookupPublicCode with odd code $code');
      Tag tag = publicTagCodeMap[code];
      if (tag != null) return tag;
  
      // **** Retired _special case_ codes that still must be handled
  