def __decodeModifier(self, keyCode):
keyName = self.lookup_string(keyCode, False, False, False)<EOL>if keyName in MODIFIERS:<EOL><INDENT>return keyName<EOL><DEDENT>return None<EOL>
Checks if the given keyCode is a modifier key. If it is, returns the modifier name
constant as defined in the iomediator module. If not, returns C{None}