valid port type before compare to min and max value

tiramisu/option.py

@@ -852,12 +852,13 @@ class PortOption(Option):
 
         for val in value:
             try:
+                int(val)
+            except ValueError:
+                raise ValueError(_('invalid port'))
             if not self._min_value <= int(val) <= self._max_value:
                 raise ValueError(_('invalid port, must be an between {0} '
                                     'and {1}').format(self._min_value,
                                                     self._max_value))
-            except ValueError:
-                raise ValueError(_('invalid port'))
 
 
 class NetworkOption(Option):