def valid_value(self, value):
    value = self.prepare_value(value)
    for (k, v) in self.choices:
        if (value == smart_text(k)):
            return True
    return False
def valid_value(self, value):
    value = self.prepare_value(value)
    for (k, v) in self.choices:
        if (value == smart_text(k)):
            return True
    return False