constructor(value, stringValue, bits /*int*/) {
			this.value = value;
			this.stringValue = stringValue;
			this.bits = bits;
			ErrorCorrectionLevel.FOR_BITS.set(bits, this);
			ErrorCorrectionLevel.FOR_VALUE.set(value, this);
		}
<p>See ISO 18004:2006, 6.5.1. This enum encapsulates the four error correction levels
defined by the QR code standard.</p>

@author Sean Owen