Update hexspeak.py

Author: kamyu104

Python/hexspeak.py

@@ -18,3 +18,15 @@ def toHexspeak(self, num):
                 return "ERROR"
             result.append(lookup[r])
         return "".join(reversed(result))
+
+
+# Time:  O(n)
+# Space: O(n)
+class Solution2(object):
+    def toHexspeak(self, num):
+        """
+        :type num: str
+        :rtype: str
+        """
+        result = hex(int(num)).upper()[2:].replace('0', 'O').replace('1', 'I')
+        return result if all(c in "ABCDEFOI" for c in result) else "ERROR"