def valid(self):
    if (not self.value):
        return True
    if (type(self.value) == self.dataType):
        return True
    else:
        return ('Wrong data type. Is %s, should be: %s.' % (type(self.value), self.dataType))
def valid(self):
    if (not self.value):
        return True
    if (type(self.value) == self.dataType):
        return True
    else:
        return ('Wrong data type. Is %s, should be: %s.' % (type(self.value), self.dataType))