                 throw ParseError.UnexpectedToken(errorMessage(tokenizer, expectedToken: Token.NUMERIC_LITERAL))
             }
         }
-        
         return coordinate
     }
 
-    private class func errorMessage(tokenizer: Tokenizer, expectedToken: Token) -> String {
-        return "Unexpected token at line: \(tokenizer.line) column: \(tokenizer.column). Expected \(expectedToken) but found -> \(tokenizer.stringStream)"
+    private func errorMessage(tokenizer: Tokenizer, expectedToken: Token) -> String {
+        return "Unexpected token at line: \(tokenizer.line) column: \(tokenizer.column). Expected \(expectedToken) but found ->\(tokenizer.stringStream)"
     }
 }

            throw ParseError.UnexpectedToken(errorMessage(tokenizer, expectedToken: Token.NUMERIC_LITERAL))
        }
        
        if tokenizer.accept(.WHITE_SPACE) == nil {
            throw ParseError.UnexpectedToken(errorMessage(tokenizer, expectedToken: Token.WHITE_SPACE))
        }
        
        if let token = tokenizer.accept(.NUMERIC_LITERAL) {

        
        if var coordinate = coordinate as? ThreeDimensional {
            
            if tokenizer.accept(.SINGLE_SPACE) == nil {
                throw ParseError.UnexpectedToken(errorMessage(tokenizer, expectedToken: Token.SINGLE_SPACE))
            }
            
            if let token = tokenizer.accept(.NUMERIC_LITERAL) {
