     public init?(byteValue: [UInt8]) {
         
         guard let length = Length(rawValue: byteValue.count)
-        else { return nil }
-        
-        let attributeOpcodeByte = byteValue[0]
-        
-        guard attributeOpcodeByte == self.dynamicType.attributeOpcode.rawValue
+            else { return nil }
+        
+        let attributeOpcodeByte = byteValue[0]
+        
+        guard attributeOpcodeByte == ATTReadByGroupTypeRequest.attributeOpcode.rawValue
             else { return nil }
         
         self.startHandle = UInt16(littleEndian: (byteValue[1], byteValue[2]))

    }
}








        
        let endHandleBytes = endHandle.littleEndianBytes
        
        return [ATTReadByGroupTypeRequest.attributeOpcode.rawValue, startHandleBytes.0, startHandleBytes.1, endHandleBytes.0, endHandleBytes.1] + type.byteValue
    }
    
    private enum Length: Int {
