function _toLower(string str) internal pure returns (string)  {
		bytes memory bStr = bytes(str);
		bytes memory bLower = new bytes(bStr.length);
		for (uint i = 0; i < bStr.length; i++) {
			
			if ((bStr[i] >= 65) && (bStr[i] <= 90)) {
				
				bLower[i] = bytes1(int(bStr[i]) + 32);
			} else {
				bLower[i] = bStr[i];
			}
		}
		return string(bLower);
	}